WorldWideScience

Sample records for carrier mobility

  1. Carrier mobilities in microcrystalline silicon films

    International Nuclear Information System (INIS)

    Bronger, T.; Carius, R.

    2007-01-01

    For a better understanding of electronic transport mechanisms in thin-film silicon solar cell quality films, we have investigated the Hall mobility for electrons in microcrystalline/amorphous silicon over a range of crystallinities and doping concentrations. We find that Hall mobility increases with increasing doping concentration in accordance with earlier measurements. With increasing amorphous fraction, the measured mobility decreases suggesting a negative influence of the additional disorder. The results suggest a differential mobility model in which mobility depends on the energy level of the carriers that contribute to the electrical current

  2. Carrier mobilities in irradiated silicon

    CERN Document Server

    Brodbeck, T J; Sloan, T; Fretwurst, E; Kuhnke, M; Lindström, G

    2002-01-01

    Using laser pulses with <1 ns duration and a 500 MHz digital oscilloscope the current pulses were investigated for p-i-n Si diodes irradiated by neutrons up to 1 MeV equivalent fluences of 2.4x10 sup 1 sup 4 n/cm sup 2. Fitting the current pulse duration as a function of bias voltage allowed measurement of mobility and saturation velocity for both electrons and holes. No significant changes in these parameters were observed up to the maximum fluence. There are indications of a non-uniform space charge distribution in heavily irradiated diodes.

  3. Solid state cloaking for electrical charge carrier mobility control

    Science.gov (United States)

    Zebarjadi, Mona; Liao, Bolin; Esfarjani, Keivan; Chen, Gang

    2015-07-07

    An electrical mobility-controlled material includes a solid state host material having a controllable Fermi energy level and electrical charge carriers with a charge carrier mobility. At least one Fermi level energy at which a peak in charge carrier mobility is to occur is prespecified for the host material. A plurality of particles are distributed in the host material, with at least one particle disposed with an effective mass and a radius that minimize scattering of the electrical charge carriers for the at least one prespecified Fermi level energy of peak charge carrier mobility. The minimized scattering of electrical charge carriers produces the peak charge carrier mobility only at the at least one prespecified Fermi level energy, set by the particle effective mass and radius, the charge carrier mobility being less than the peak charge carrier mobility at Fermi level energies other than the at least one prespecified Fermi level energy.

  4. Anisotropic charged impurity-limited carrier mobility in monolayer phosphorene

    International Nuclear Information System (INIS)

    Ong, Zhun-Yong; Zhang, Gang; Zhang, Yong Wei

    2014-01-01

    The room temperature carrier mobility in atomically thin 2D materials is usually far below the intrinsic limit imposed by phonon scattering as a result of scattering by remote charged impurities in its environment. We simulate the charged impurity-limited carrier mobility μ in bare and encapsulated monolayer phosphorene. We find a significant temperature dependence in the carrier mobilities (μ ∝ T −γ ) that results from the temperature variability of the charge screening and varies with the crystal orientation. The anisotropy in the effective mass leads to an anisotropic carrier mobility, with the mobility in the armchair direction about one order of magnitude larger than in the zigzag direction. In particular, this mobility anisotropy is enhanced at low temperatures and high carrier densities. Under encapsulation with a high-κ overlayer, the mobility increases by up to an order of magnitude although its temperature dependence and its anisotropy are reduced

  5. Anisotropic charged impurity-limited carrier mobility in monolayer phosphorene

    Energy Technology Data Exchange (ETDEWEB)

    Ong, Zhun-Yong; Zhang, Gang; Zhang, Yong Wei [Institute of High Performance Computing, A*STAR, Singapore 138632 (Singapore)

    2014-12-07

    The room temperature carrier mobility in atomically thin 2D materials is usually far below the intrinsic limit imposed by phonon scattering as a result of scattering by remote charged impurities in its environment. We simulate the charged impurity-limited carrier mobility μ in bare and encapsulated monolayer phosphorene. We find a significant temperature dependence in the carrier mobilities (μ ∝ T{sup −γ}) that results from the temperature variability of the charge screening and varies with the crystal orientation. The anisotropy in the effective mass leads to an anisotropic carrier mobility, with the mobility in the armchair direction about one order of magnitude larger than in the zigzag direction. In particular, this mobility anisotropy is enhanced at low temperatures and high carrier densities. Under encapsulation with a high-κ overlayer, the mobility increases by up to an order of magnitude although its temperature dependence and its anisotropy are reduced.

  6. Importance of polaron effects for charge carrier mobility above and ...

    Indian Academy of Sciences (India)

    Orifjon Ganiev

    2017-05-30

    May 30, 2017 ... sizes and effective masses are large polarons. According ... nating metallic and insulating domains with mobile ... The mobile polaronic carriers are con- ..... [51] T Kondo, Y Hamaya, A D Palczewski, T Takeuchi, J S Wen,.

  7. Disorder effect on carrier mobility in Fullerene organic semiconductor

    International Nuclear Information System (INIS)

    Mendil, N; Daoudi, M; Berkai, Z; Belghachi, A

    2015-01-01

    The critical factor that limits the efficiencies of organic electronic devices is the low charge carrier mobility which is attributed to disorder in organic films. In this context, we have studied the effects of disorder on carrier mobility in organic Schottky diode of electrons for the fullerene (C 60 ). Our results show that the mobility is sensitive probes of structural phase transitions and order-disorder underlying C 60 . Where it is one reason behind the low mobility which it take as value 1.4x10 -2 cm 2 /V.s above critical temperature Tc =289K. (paper)

  8. Mobility of charge carriers in porous silicon layers

    International Nuclear Information System (INIS)

    Forsh, P. A.; Martyshov, M. N.; Latysheva, A. P.; Vorontsov, A. S.; Timoshenko, V. Yu.; Kashkarov, P. K.

    2008-01-01

    The (conduction) mobility of majority charge carriers in porous silicon layers of the n and p types is estimated by joint measurements of electrical conductivity and free charge carrier concentration, which is determined from IR absorption spectra. Adsorption of donor and acceptor molecules leading to a change in local electric fields in the structure is used to identify the processes controlling the mobility in porous silicon. It is found that adsorption of acceptor and donor molecules at porous silicon of the p and n types, respectively, leads to a strong increase in electrical conductivity, which is associated with an increase in the concentration of free carrier as well as in their mobility. The increase in the mobility of charge carriers as a result of adsorption indicates the key role of potential barriers at the boundaries of silicon nanocrystals and may be due to a decrease in the barrier height as a result of adsorption

  9. Importance of polaron effects for charge carrier mobility above and ...

    Indian Academy of Sciences (India)

    It is shown that the scattering of polaronic charge carriers and bosonic Cooper pairs at acoustic and optical phonons are responsible for the charge carrier mobility above and below the PG temperature. We show that the energy scales of the binding energies of large polarons and polaronic Cooper pairs can be identified by ...

  10. Charge-carrier mobilities in disordered semiconducting polymers: effects of carrier density and electric field [refereed

    NARCIS (Netherlands)

    Meisel, K.D.; Pasveer, W.F.; Cottaar, J.; Tanase, C.; Coehoorn, R.; Bobbert, P.A.; Blom, P.W.M.; Leeuw, de D.M.; Michels, M.A.J.

    2006-01-01

    We model charge transport in disordered semiconducting polymers by hopping of charge carriers on a square lattice of sites with Gaussian on-site energy disorder, using Fermi-Dirac statistics. From numerically exact solns. of the Master equation, we study the dependence of the charge-carrier mobility

  11. Photoinduced reversible switching of charge carrier mobility in conjugated polymers

    Czech Academy of Sciences Publication Activity Database

    Weiter, M.; Navrátil, J.; Vala, M.; Toman, Petr

    2009-01-01

    Roč. 48, č. 1 (2009), 10401_1-10401_6 ISSN 1286-0042 R&D Projects: GA ČR GA203/06/0285; GA AV ČR KAN401770651 Institutional research plan: CEZ:AV0Z40500505 Keywords : polymers * switch * charge carrier mobility Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.756, year: 2009

  12. Intrinsic Charge Carrier Mobility in Single-Layer Black Phosphorus.

    Science.gov (United States)

    Rudenko, A N; Brener, S; Katsnelson, M I

    2016-06-17

    We present a theory for single- and two-phonon charge carrier scattering in anisotropic two-dimensional semiconductors applied to single-layer black phosphorus (BP). We show that in contrast to graphene, where two-phonon processes due to the scattering by flexural phonons dominate at any practically relevant temperatures and are independent of the carrier concentration n, two-phonon scattering in BP is less important and can be considered negligible at n≳10^{13}  cm^{-2}. At smaller n, however, phonons enter in the essentially anharmonic regime. Compared to the hole mobility, which does not exhibit strong anisotropy between the principal directions of BP (μ_{xx}/μ_{yy}∼1.4 at n=10^{13} cm^{-2} and T=300  K), the electron mobility is found to be significantly more anisotropic (μ_{xx}/μ_{yy}∼6.2). Absolute values of μ_{xx} do not exceed 250 (700)  cm^{2} V^{-1} s^{-1} for holes (electrons), which can be considered as an upper limit for the mobility in BP at room temperature.

  13. 77 FR 14012 - Eligible Telecommunications Carrier Designation for Participation in Mobility Fund Phase I

    Science.gov (United States)

    2012-03-08

    ...; DA 12-271] Eligible Telecommunications Carrier Designation for Participation in Mobility Fund Phase I... Wireless Telecommunications and Wireline Competition Bureaus describe the process and requirements for applicants seeking Eligible Telecommunications Carrier (ETC) Designation from the Commission for...

  14. Carrier mobility and crystal perfection of tetracene thin film FET

    International Nuclear Information System (INIS)

    Moriguchi, N.; Nishikawa, T.; Anezaki, T.; Unno, A.; Tachibana, M.; Kojima, K.

    2006-01-01

    It is well-known that the carrier mobility of an organic field effect semiconductor (FET) depended on the crystal quality and/or the crystal perfection of the organic thin films [T.W. Kelly, D.V. Muyres, P.F. Baude, T.P. Smith, T.D. Jones, Mater. Res. Soc. Symp. Proc. 771 (2003) L6.5.1; D.J. Gundlach, J.A. Nichols, L. Zhou, T.N. Jackson, Appl. Phys. Lett. 80 (2002) 2925; H.K. Lauk, M. Halik, U. Zschieschang, G. Schmid, W. Radlik, J. Appl. Phys. 92 (2002) 5259; M. Shtein, J. Mapel, J.B. Benziger, S.R. Forrest, Appl. Phys. Lett. 81 (2002) 268; D. Knipp, R.A. Street, A.R. Volkel, Appl. Phys. Lett. 82 (2003) 3907; R. Ruiz, A.C. Mayer, G.G. Malliaras, Appl. Phys. Lett. 85 (2004) 4926; R.W.I. de Boer, M.E. Gershenson, A.F. Morpurgo, V. Podzorov, Phys. Stat. Sol. A 201 (2004) 1031]. To improve the crystal quality of the thin film many efforts were made. One of the important improvements was the surface treatment of the substrate. The tetracene thin film FET (top contact structure) was fabricated using the substrate, which was coated by a spin-coating method with a 0.1% poly α-methylstyrene (AMS) solution. The crystal quality was improved by this treatment so that the carrier mobility was higher than that of non-treatment. The maximum mobility of the AMS-treated sample was obtained to be 0.12 cm 2 /V s

  15. Tuning carrier mobility of phosphorene nanoribbons by edge passivation and strain

    International Nuclear Information System (INIS)

    Zhang, Xiaoou; Li, Qingfang; Xu, Bo; Wan, Bo; Yin, Jiang; Wan, X.G.

    2016-01-01

    Using first-principles calculations, we have studied the effects of different edge passivation groups on the carrier mobility of the phosphorene nanoribbons (PNRs) and strain effect on the transport property in passivated PNRs. The numerical results show that the size-dependent carrier mobility of passivated PNRs is not very sensitive to the different passivation groups, such as hydrogen (H), fluorine (F) and chlorine (Cl), but strongly associated with the orientation of nanoribbons. Passivated armchair-PNR has much larger carrier mobility than passivated zigzag-PNR at the similar ribbon width. With increasing ribbon width, the electron mobility of passivated PNRs can be further enhanced. We also find that the anisotropy of carrier mobility in passivated PNRs can be reversed by applying tensile strain resulting from order switching of the conduction bands around Fermi level.

  16. Tuning carrier mobility of phosphorene nanoribbons by edge passivation and strain

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaoou [National Laboratory of Solid State Microstructures, College of Physics, Nanjing University, Nanjing 210093 (China); Li, Qingfang, E-mail: qingfangli@nuist.edu.cn [National Laboratory of Solid State Microstructures, College of Physics, Nanjing University, Nanjing 210093 (China); Department of Physics, Nanjing University of Information Science & Technology, Nanjing 210044 (China); Xu, Bo, E-mail: xubonju@gmail.com [National Laboratory of Solid State Microstructures and Department of Materials Science and Engineering, Nanjing University, Nanjing 210093 (China); Wan, Bo [National Laboratory of Solid State Microstructures, College of Physics, Nanjing University, Nanjing 210093 (China); Yin, Jiang [National Laboratory of Solid State Microstructures and Department of Materials Science and Engineering, Nanjing University, Nanjing 210093 (China); Wan, X.G. [National Laboratory of Solid State Microstructures, College of Physics, Nanjing University, Nanjing 210093 (China)

    2016-02-05

    Using first-principles calculations, we have studied the effects of different edge passivation groups on the carrier mobility of the phosphorene nanoribbons (PNRs) and strain effect on the transport property in passivated PNRs. The numerical results show that the size-dependent carrier mobility of passivated PNRs is not very sensitive to the different passivation groups, such as hydrogen (H), fluorine (F) and chlorine (Cl), but strongly associated with the orientation of nanoribbons. Passivated armchair-PNR has much larger carrier mobility than passivated zigzag-PNR at the similar ribbon width. With increasing ribbon width, the electron mobility of passivated PNRs can be further enhanced. We also find that the anisotropy of carrier mobility in passivated PNRs can be reversed by applying tensile strain resulting from order switching of the conduction bands around Fermi level.

  17. Mobility of delocalized charge carriers in an ideal homopolar glass as a function of temperature

    International Nuclear Information System (INIS)

    Iskra, V.D.

    1986-01-01

    The relationship between temperature and the mobility of delocalized charge carriers for an intrinsic random field of a homopolar glass is investigated through application of a method of scattering amplitude calculation based on employing short-lived potential factorization

  18. Mobility Analysis for Inter-Site Carrier Aggregation in LTE Heterogeneous Networks

    DEFF Research Database (Denmark)

    Barbera, Simone; Pedersen, Klaus I.; Michaelsen, Per Henrik

    2013-01-01

    In this paper we analyze the mobility performance for an LTE Heterogeneous Network with macro and pico cells deployed on different carriers. Cases with/without downlink inter-site carrier aggregation are investigated. Extensive system level simulations are exploited to quantify the performance...

  19. Charge-carrier mobilities in disordered semiconducting polymers : effects of carrier density and electric field

    NARCIS (Netherlands)

    Meisel, K.D.; Pasveer, W.F.; Cottaar, J.; Tanase, C.; Coehoorn, R.; Bobbert, P.A.; Blom, P.W.M.; Leeuw, D.M. de; Michels, M.A.J.

    2006-01-01

    We model charge transport in disordered semiconducting polymers by hopping of charge carriers on a square lattice of sites with Gaussian on-site energy disorder, using Fermi-Dirac statistics. From numerically exact solutions of the Master equation, we study the dependence of the charge-carrier

  20. Determination of charge carrier mobility in doped low density polyethylene using DC transients

    DEFF Research Database (Denmark)

    Khalil, M.Salah; Henk, Peter O; Henriksen, Mogens

    1989-01-01

    Charge carrier mobility was determined for plain and doped low-density polyethylene (LDPE) using DC transient currents. Barium titanate was used as a strongly polar dopant and titanium dioxide as a semiconductor dopant. The values of the mobility obtained were on the order of 10-10 cm2 v-1 s-1...

  1. Hall mobility of free charge carriers in highly compensated p-Germanium

    International Nuclear Information System (INIS)

    Gavrilyuk, V.Yi.; Kirnas, Yi.G.; Balakyin, V.D.

    2000-01-01

    Hall mobility of free charge carriers in initial detectors Ge (Ga) is studied. It is established that an increase in the compensation factor results in the enlargement of Hall mobility in germanium highly compensated by introduction of Li ions during their drift in an electrical field

  2. Large enhancements of thermopower and carrier mobility in quantum dot engineered bulk semiconductors.

    Science.gov (United States)

    Liu, Yuanfeng; Sahoo, Pranati; Makongo, Julien P A; Zhou, Xiaoyuan; Kim, Sung-Joo; Chi, Hang; Uher, Ctirad; Pan, Xiaoqing; Poudeu, Pierre F P

    2013-05-22

    The thermopower (S) and electrical conductivity (σ) in conventional semiconductors are coupled adversely through the carriers' density (n) making it difficult to achieve meaningful simultaneous improvements in both electronic properties through doping and/or substitutional chemistry. Here, we demonstrate the effectiveness of coherently embedded full-Heusler (FH) quantum dots (QDs) in tailoring the density, mobility, and effective mass of charge carriers in the n-type Ti(0.1)Zr(0.9)NiSn half-Heusler matrix. We propose that the embedded FH QD forms a potential barrier at the interface with the matrix due to the offset of their conduction band minima. This potential barrier discriminates existing charge carriers from the conduction band of the matrix with respect to their relative energy leading to simultaneous large enhancements of the thermopower (up to 200%) and carrier mobility (up to 43%) of the resulting Ti(0.1)Zr(0.9)Ni(1+x)Sn nanocomposites. The improvement in S with increasing mole fraction of the FH-QDs arises from a drastic reduction (up to 250%) in the effective carrier density coupled with an increase in the carrier's effective mass (m*), whereas the surprising enhancement in the mobility (μ) is attributed to an increase in the carrier's relaxation time (τ). This strategy to manipulate the transport behavior of existing ensembles of charge carriers within a bulk semiconductor using QDs is very promising and could pave the way to a new generation of high figure of merit thermoelectric materials.

  3. Charge carrier mobility in thin films of organic semiconductors by the gated van der Pauw method

    Science.gov (United States)

    Rolin, Cedric; Kang, Enpu; Lee, Jeong-Hwan; Borghs, Gustaaf; Heremans, Paul; Genoe, Jan

    2017-01-01

    Thin film transistors based on high-mobility organic semiconductors are prone to contact problems that complicate the interpretation of their electrical characteristics and the extraction of important material parameters such as the charge carrier mobility. Here we report on the gated van der Pauw method for the simple and accurate determination of the electrical characteristics of thin semiconducting films, independently from contact effects. We test our method on thin films of seven high-mobility organic semiconductors of both polarities: device fabrication is fully compatible with common transistor process flows and device measurements deliver consistent and precise values for the charge carrier mobility and threshold voltage in the high-charge carrier density regime that is representative of transistor operation. The gated van der Pauw method is broadly applicable to thin films of semiconductors and enables a simple and clean parameter extraction independent from contact effects. PMID:28397852

  4. Effect of phosphorus dopant concentration on the carrier mobility in ...

    African Journals Online (AJOL)

    This study investigated the effect of phosphorus dopant concentration on mobility of crystalline silicon (c-Si). It considers different temperature ranges, from 100 K to 500 K, and dopant concentration from 1012 cm-3 to 1020 cm-3 in relation to its effect on the mobility of the crystalline silicon. This study indicates that the ...

  5. Diverse carrier mobility of monolayer BNCx: A combined density functional theory and Boltzmann transport theory study.

    Science.gov (United States)

    Wu, Tao; Deng, Kaiming; Deng, Wei-Qiao; Lu, Ruifeng

    2017-09-19

    BNCX monolayer as a kind of two-dimensional material has numerous chemical atomic ratios and arrangements with different electronic structures. Via calculations on the basis of density functional theory and Boltzmann transport theory under deformation potential approximation, the band structures and carrier mobilities of BNCX (x=1,2,3,4) nanosheets are systematically investigated. The calculated results show that BNC2-1 is a material with very small band gap (0.02 eV) among all the structures while other BNCX monolayers are semiconductors with band gap ranging from 0.51 to 1.32 eV. The carrier mobility of BNCX varies considerably from tens to millions of cm2 V-1 s-1. For BNC2-1, the hole mobility and electron mobility along both x and y directions can reach 105 orders of magnitude, which is similar to the carrier mobility of graphene. Besides, all studied BNCX monolayers obviously have anisotropic hole mobility and electron mobility. In particular, for semiconductor BNC4, its hole mobility along y direction and electron mobility along x direction unexpectedly reach 106 orders of magnitude, even higher than that of graphene. Our findings suggest that BNCX layered materials with proper ratio and arrangement of carbon atoms will possess desirable charge transport properties, exhibiting potential applications in nanoelectronic devices. © 2017 IOP Publishing Ltd.

  6. Unveiling the Structural Origin of the High Carrier Mobility of a Molecular Monolayer on Boron Nitride

    OpenAIRE

    Xu, Rui; He, Daowei; Zhang, Yuhan; Wu, Bing; Liu, Fengyuan; Meng, Lan; Liu, Jun-Fang; Wu, Qisheng; Shi, Yi; Wang, Jinlan; Nie, Jia-Cai; Wang, Xinran; He, Lin

    2014-01-01

    Very recently, it was demonstrated that the carrier mobility of a molecular monolayer dioctylbenzothienobenzothiophene (C8-BTBT) on boron nitride can reach 10 cm2/Vs, the highest among the previously reported monolayer molecular field-effect transistors. Here we show that the high-quality single crystal of the C8-BTBT monolayer may be the key origin of the record-high carrier mobility. We discover that the C8-BTBT molecules prefer layer-by-layer growth on both hexagonal boron nitride and grap...

  7. A self-consistent first-principle based approach to model carrier mobility in organic materials

    International Nuclear Information System (INIS)

    Meded, Velimir; Friederich, Pascal; Symalla, Franz; Neumann, Tobias; Danilov, Denis; Wenzel, Wolfgang

    2015-01-01

    Transport through thin organic amorphous films, utilized in OLEDs and OPVs, has been a challenge to model by using ab-initio methods. Charge carrier mobility depends strongly on the disorder strength and reorganization energy, both of which are significantly affected by the details in environment of each molecule. Here we present a multi-scale approach to describe carrier mobility in which the materials morphology is generated using DEPOSIT, a Monte Carlo based atomistic simulation approach, or, alternatively by molecular dynamics calculations performed with GROMACS. From this morphology we extract the material specific hopping rates, as well as the on-site energies using a fully self-consistent embedding approach to compute the electronic structure parameters, which are then used in an analytic expression for the carrier mobility. We apply this strategy to compute the carrier mobility for a set of widely studied molecules and obtain good agreement between experiment and theory varying over several orders of magnitude in the mobility without any freely adjustable parameters. The work focuses on the quantum mechanical step of the multi-scale workflow, explains the concept along with the recently published workflow optimization, which combines density functional with semi-empirical tight binding approaches. This is followed by discussion on the analytic formula and its agreement with established percolation fits as well as kinetic Monte Carlo numerical approaches. Finally, we skatch an unified multi-disciplinary approach that integrates materials science simulation and high performance computing, developed within EU project MMM@HPC

  8. Intrinsic carrier mobility extraction based on a new quasi-analytical model for graphene field-effect transistors

    International Nuclear Information System (INIS)

    Wang, Shaoqing; Jin, Zhi; Muhammad, Asif; Peng, Songang; Huang, Xinnan; Zhang, Dayong; Shi, Jingyuan

    2016-01-01

    The most common method of mobility extraction for graphene field-effect transistors is proposed by Kim. Kim’s method assumes a constant mobility independent of carrier density and gets the mobility by fitting the transfer curves. However, carrier mobility changes with the carrier density, leading to the inaccuracy of Kim’s method. In our paper, a new and more accurate method is proposed to extract mobility by fitting the output curves at a constant gate voltage. The output curves are fitted using several kinds of current–voltage models. Besides the models in the literature, we present a modified model, which takes into account not only the quantum capacitance, contact resistance, but also a modified drift velocity-field relationship. Comparing with the other models, this new model can fit better with our experimental data. The dependence of carrier intrinsic mobility on carrier density is obtained based on this model. (paper)

  9. Theoretical prediction of high carrier mobility in single-walled black phosphorus nanotubes

    Science.gov (United States)

    Li, Q. F.; Wang, H. F.; Yang, C. H.; Li, Q. Q.; Rao, W. F.

    2018-05-01

    One-dimensional semiconductors are promising materials for high-performance nanoscale devices. Using the first-principles calculations combined with deformation potential approximation, we study the electronic structures and carrier transport properties of black phosphorus nanotubes (BPNTs). It is found that both armchair and zigzag BPNTs with diameter 13.5-18.5 Å are direct bandgap semiconductors. At a similar diameter, the carrier mobility of zigzag BPNT is one order of magnitude larger than that of armchair BPNT. For armchair BPNTs, the electron mobility is about 90.70-155.33 cm2 V-1 s-1 at room temperature, which is about three times of its hole counterpart. For zigzag BPNTs, the maximum mobility can reach 2.87 ×103 cm2 V-1 s-1. Furthermore, the electronic properties can be effectively tuned by the strain. For zigzag (0,13) nanotube, there is a direct-to-indirect band gap transition at a tensile strain of about 6%. Moreover, the electron mobility is boosted sharply by one order of magnitude by applying the compressive or tensile strain. The electron mobility increases to 14.05 ×103 cm2 V-1 s-1 at a tensile strain of 9%. Our calculations highlight the tunable electronic properties and superior carrier mobility of BPNTs that are promising for interesting applications in future nano-electronic devices.

  10. Theoretical modeling of influence of the structural disorder on the charge carrier mobility in triphenylene stacks

    Czech Academy of Sciences Publication Activity Database

    Mikolajczyk, M.; Toman, Petr; Bartkowiak, W.

    2010-01-01

    Roč. 485, 1-3 (2010), s. 253-257 ISSN 0009-2614 R&D Projects: GA MŠk MEB050815; GA AV ČR IAA401770601 Institutional research plan: CEZ:AV0Z40500505 Keywords : triphenylene * charge carrier mobility * tight-binding approximation Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.282, year: 2010

  11. Contribution of current carrier mobility variation to piezo-resistive effect in SmS

    International Nuclear Information System (INIS)

    Vasil'ev, L.N.; Kaminskij, V.V.

    1999-01-01

    The value of the contribution from the change in the current carriers mobility and pressure to the piezo-resistive effect value in the materials on the basis of the samarium, monosulfide is studied. The conclusion, that the value of the piezoresistance of comprehensive compression should not exceed 7x10 -3 MPa -1 at T=300 K, experimental data [ru

  12. Studies of the mobility of charge carriers in low-dimensional systems in a transverse DC electric field

    Energy Technology Data Exchange (ETDEWEB)

    Sinyavskii, E. P., E-mail: sinyavskii@gmail.com [Academy of Sciences of Moldova, Institute of Applied Physics (Moldova, Republic of); Karapetyan, S. A., E-mail: karapetyan.sa@gmail.com [Shevchenko Pridnestrovskii State University (Moldova, Republic of)

    2011-08-15

    The mobility of charge carriers {mu} in a parabolic quantum well in an electric field E directed along the size-confinement axis is calculated. With consideration for scattering of charge carriers at a rough surface, the mobility {mu} is shown to decrease with increasing E. A physical interpretation of this effect is proposed.

  13. Anisotropic carrier mobility in single- and bi-layer C3N sheets

    Science.gov (United States)

    Wang, Xueyan; Li, Qingfang; Wang, Haifeng; Gao, Yan; Hou, Juan; Shao, Jianxin

    2018-05-01

    Based on the density functional theory combined with the Boltzmann transport equation with relaxation time approximation, we investigate the electronic structure and predict the carrier mobility of single- and bi-layer newly fabricated 2D carbon nitrides C3N. Although C3N sheets possess graphene-like planar hexagonal structure, the calculated carrier mobility is remarkably anisotropic, which is found mainly induced by the anisotropic effective masses and deformation potential constants. Importantly, we find that both the electron and hole mobilities are considerable high, for example, the hole mobility along the armchair direction of single-layer C3N sheets can arrive as high as 1.08 ×104 cm2 V-1 s-1, greatly larger than that of C2N-h2D and many other typical 2D materials. Owing to the high and anisotropic carrier mobility and appropriate band gap, single- and bi-layer semiconducting C3N sheets may have great potential applications in high performance electronic and optoelectronic devices.

  14. Supermolecular structure and charge carriers mobilities of perylene diimides

    Energy Technology Data Exchange (ETDEWEB)

    Marcon, Valentina; Pisula, Wojtek; Andrienko, Denis [Max-Planck-Institut fuer Polymerforschung, Mainz (Germany); Kirkpatrick, James [Max-Planck-Institut fuer Polymerforschung, Mainz (Germany); Department of Physics, Imperial College London, London (United Kingdom)

    2008-07-01

    Perylene diimides form columnar phases, where the molecules stack on top of each other and the columns arrange in a regular lattice. The self-organization into well-ordered columns results in the one-dimensional charge transport along the stack of the aromatic cores of the molecules. Most of the discotic molecules which organize in columns are p-type semiconductors, while the class of rylene diimide molecules, to which perylene belongs, forms n-type organic semiconductors. Using atomistic molecular dynamics (MD) simulations we study the columnar phases of perylene diimides and establish correlations between the molecular structure, packing, and dynamical properties of these materials. By using a scheme which combines electronic structure calculations, MD and kinetic Monte Carlo simulations, a correlation is then established between the molecular structure and charge mobility of perylenes columnar mesophases.

  15. Towards predictive many-body calculations of phonon-limited carrier mobilities in semiconductors

    Science.gov (United States)

    Poncé, Samuel; Margine, Elena R.; Giustino, Feliciano

    2018-03-01

    We probe the accuracy limit of ab initio calculations of carrier mobilities in semiconductors, within the framework of the Boltzmann transport equation. By focusing on the paradigmatic case of silicon, we show that fully predictive calculations of electron and hole mobilities require many-body quasiparticle corrections to band structures and electron-phonon matrix elements, the inclusion of spin-orbit coupling, and an extremely fine sampling of inelastic scattering processes in momentum space. By considering all these factors we obtain excellent agreement with experiment, and we identify the band effective masses as the most critical parameters to achieve predictive accuracy. Our findings set a blueprint for future calculations of carrier mobilities, and pave the way to engineering transport properties in semiconductors by design.

  16. Influence of packing motives on charge Carrier mobility in perylene tetracarboxdiimide derivatives

    Energy Technology Data Exchange (ETDEWEB)

    May, Falk; Andrienko, Denis [Max-Planck Institute for Polymer Research, Mainz (Germany); Marcon, Valentina [Center of Smart Interfaces, Darmstadt (Germany)

    2010-07-01

    Discotic mesophases are known for their ability to self-assemble into columnar structures and can serve as semiconducting molecular wires. Charge carrier mobility along these wires strongly depends on molecular packing which is controlled by intermolecular interactions. In this work we compare the influence of side chains on the packing motives of perylene tetracarboxdiimide (PDI) derivatives. Two different (alkyl and glycol) side chains are considered. We first establish how the packing of side chains affects the molecular orientation within the columns using molecular dynamics. Then, using the high temperature non-adiabatic limit of Marcus theory for hopping rates and solving the rate equation for charge transport, we analyze the link between the secondary structure and charge carrier mobility. This analysis eventually provides a pathway to rational design of columnar assemblies of PDI derivatives with high charge mobilities.

  17. Carrier mobility and scattering lifetime in electric double-layer gated few-layer graphene

    Energy Technology Data Exchange (ETDEWEB)

    Piatti, E.; Galasso, S.; Tortello, M.; Nair, J.R.; Gerbaldi, C. [Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, 10129 Torino (Italy); Bruna, M.; Borini, S. [Istituto Nazionale di Ricerca Metrologica (INRIM), 10135 Torino (Italy); Daghero, D. [Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, 10129 Torino (Italy); Gonnelli, R.S., E-mail: renato.gonnelli@polito.it [Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, 10129 Torino (Italy)

    2017-02-15

    Highlights: • We fabricated few-layer graphene FETs by mechanical exfoliation and standard microfabrication techniques. • We employed a Li-TFSI based ion gel to induce carrier densities as high as ≈6e14 e{sup −}/cm{sup 2} in the devices' channel. • We found a strong asymmetry in the sheet conductance and mobility doping dependences between electron and hole doping. • We combined the experimental results with ab initio DFT calculations to obtain the average scattering lifetime of the charge carriers. • We found that the increase in the carrier density and an unexpected increase in the density of charged scattering centers compete in determining the scattering lifetime. - Abstract: We fabricate electric double-layer field-effect transistor (EDL-FET) devices on mechanically exfoliated few-layer graphene. We exploit the large capacitance of a polymeric electrolyte to study the transport properties of three, four and five-layer samples under a large induced surface charge density both above and below the glass transition temperature of the polymer. We find that the carrier mobility shows a strong asymmetry between the hole and electron doping regime. We then employ ab initio density functional theory (DFT) calculations to determine the average scattering lifetime from the experimental data. We explain its peculiar dependence on the carrier density in terms of the specific properties of the electrolyte we used in our experiments.

  18. Determination of Charge-Carrier Mobility in Disordered Thin-Film Solar Cells as a Function of Current Density

    Science.gov (United States)

    Mäckel, Helmut; MacKenzie, Roderick C. I.

    2018-03-01

    Charge-carrier mobility is a fundamental material parameter, which plays an important role in determining solar-cell efficiency. The higher the mobility, the less time a charge carrier will spend in a device and the less likely it is that it will be lost to recombination. Despite the importance of this physical property, it is notoriously difficult to measure accurately in disordered thin-film solar cells under operating conditions. We, therefore, investigate a method previously proposed in the literature for the determination of mobility as a function of current density. The method is based on a simple analytical model that relates the mobility to carrier density and transport resistance. By revising the theoretical background of the method, we clearly demonstrate what type of mobility can be extracted (constant mobility or effective mobility of electrons and holes). We generalize the method to any combination of measurements that is able to determine the mean electron and hole carrier density, and the transport resistance at a given current density. We explore the robustness of the method by simulating typical organic solar-cell structures with a variety of physical properties, including unbalanced mobilities, unbalanced carrier densities, and for high or low carrier trapping rates. The simulations reveal that near VOC and JSC , the method fails due to the limitation of determining the transport resistance. However, away from these regions (and, importantly, around the maximum power point), the method can accurately determine charge-carrier mobility. In the presence of strong carrier trapping, the method overestimates the effective mobility due to an underestimation of the carrier density.

  19. Germanium Doping to Improve Carrier Mobility in CdO Films

    Directory of Open Access Journals (Sweden)

    A. A. Dakhel

    2013-01-01

    Full Text Available This investigation addresses the structural, optical, and electrical properties of germanium incorporated cadmium oxide (CdO : Ge thin films. The focus was on the improvement in carrier mobility to achieve high transparency for near-infrared light and low resistivity at the same time. The properties were studied using X-ray diffraction, SEM, spectral photometry, and Hall measurements. All CdO : Ge films were polycrystalline with high texture orientation along [111] direction. It was observed that it is possible to control the carrier concentration ( and mobility ( with Ge-incorporation level. The mobility could be improved to a highest value of  cm2/V·s with Ge doping of 0.25 wt% while maintaining the electrical resistivity as low as  Ω·cm and good transparency % in the NIR spectral region. The results of the present work proved to select Ge as dopant to achieve high carrier mobility with low resistivity for application in transparent conducting oxide (TCO field. Generally, the properties found make CdO : Ge films particularly interesting for the application in optoelectronic devices like thin-film solar cells.

  20. Hopping mobility of charge carriers in polymers in the earliest stages after their generation

    International Nuclear Information System (INIS)

    Tyutnev, A.P.; Subbotin, A.V.; Chekunaev, N.I.

    1989-01-01

    It has been found that both the photo- and the radiation conductivity of a number of polymers (primarily polyvinylcarbazole, polystyrene, and polyethylene terephthalate) are of a molecular nature, and movement of the generated charge carriers is by a hopping and not by a band mechanism. Analytical expressions for the instantaneous effective mobility and effective displacement of charge carriers in a unitary electric field were obtained in the approximation of isolated pairs of nearest neighbors for four species (monoenergetic, exponential, Gaussian, and bilevel) of energy application of hopping sites randomly distributed in space. Problems of the application of these expressions to real polymers are discussed on the example of polyvinylcarbazole

  1. The impact of occupational load carriage on carrier mobility: a critical review of the literature.

    Science.gov (United States)

    Carlton, Simon D; Orr, Robin M

    2014-01-01

    Military personnel and firefighters are required to carry occupational loads and complete tasks in hostile and unpredictable environments where a lack of mobility may risk lives. This review critically examines the literature investigating the impacts of load carriage on the mobility of these specialist personnel. Several literature databases, reference lists, and subject matter experts were employed to identify relevant studies. Studies meeting the inclusion criteria were critiqued using the Downs and Black protocol. Inter-rater agreement was determined by Cohen's κ. Twelve original research studies, which included male and female participants from military and firefighting occupations, were critiqued (κ = .81). A review of these papers found that as the carried load weight increased, carrier mobility during aerobic tasks (like road marching) and anaerobic tasks (like obstacle course negotiation) decreased. As such, it can be concluded that the load carried by some specialist personnel may increase their occupational risk by reducing their mobility.

  2. Calculated carrier mobility of h-BN/γ-InSe/h-BN van der Waals heterostructures

    Science.gov (United States)

    Kang, P.; Michaud-Rioux, V.; Kong, X.-H.; Yu, G.-H.; Guo, H.

    2017-12-01

    Recent experiments reported excellent transport properties of two-dimensional (2D) van der Waals (vdW) heterostructures made of atomically thin InSe layers encapsulated by two hBN capping layers (ISBN). The carrier mobility of the ISBN films exceeded μ ˜ 1.2× {{10}4} \\text{c}{{\\text{m}}2} {{\\text{V}}-1} {{\\text{s}}-1} at low temperature, much higher than that of pristine InSe films. It has been puzzling why the relatively inert hBN capping layer could so drastically enhance mobility of the ISBN composite. Using a state-of-the-art first principles method, we have calculated phonon limited carrier mobility of 18 different ISBN films and 6 pristine InSe films with different thicknesses, the largest system containing 2212 atoms. The hBN capping layer significantly alters the elastic stiffness coefficient as compared with pure InSe—thus the acoustic phonons in the ISBN composite—giving rise to the observed large mobility of ISBN films. Of the 18 calculated ISBN films, the ones with no strain at the hBN/InSe interface possess the highest electron mobility, reaching 4340~\\text{c}{{\\text{m}}2}~{{\\text{V}}-1}~{{\\text{s}}-1} at room temperature, which could easily go over {{10}4}~\\text{c}{{\\text{m}}2}~{{\\text{V}}-1}~{{\\text{s}}-1} at low temperatures. We conclude that the mechanical properties of the composite 2D vdW ISBN material play the crucial role for inducing the large carrier mobility, a principle that could be applied to many other 2D vdW heterostructures.

  3. Low-field mobility and carrier transport mechanism transition in nanoscale MOSFETs

    International Nuclear Information System (INIS)

    Liu Hongwei; Wang Runsheng; Huang Ru; Zhang Xing

    2010-01-01

    This paper extends the flux scattering method to study the carrier transport property in nanoscale MOSFETs with special emphasis on the low-field mobility and the transport mechanism transition. A unified analytical expression for the low-field mobility is proposed, which covers the entire regime from drift-diffusion transport to quasi-ballistic transport in 1-D, 2-D and 3-D MOSFETs. Two key parameters, namely the long-channel low-field mobility (μ 0 ) and the low-field mean free path (λ 0 ), are obtained from the experimental data, and the transport mechanism transition in MOSFETs is further discussed both experimentally and theoretically. Our work shows that λ 0 is available to characterize the inherent transition of the carrier transport mechanism rather than the low-field mobility. The mobility reduces in the MOSFET with the shrinking of the channel length; however, λ 0 is nearly a constant, and λ 0 can be used as the 'entry criterion' to determine whether the device begins to operate under quasi-ballistic transport to some extent. (semiconductor devices)

  4. Density and mobility effects of the majority carriers in organic semiconductors under light excitation

    Energy Technology Data Exchange (ETDEWEB)

    Vagenas, N.; Giannopoulou, A.; Kounavis, P., E-mail: pkounavis@upatras.gr [Department of Electrical and Computer Engineering, University of Patras, 26504 Patra (Greece)

    2015-01-21

    This study demonstrates that the effect of light excitation on the density and the mobility of the majority carriers can be explored in organic semiconductors by modulated photocurrent spectroscopy. The spectra of phase and amplitude of the modulated photocurrent of pentacene films indicate a significant increase in the density of the photogenerated mobile holes (majority carriers). This increase is accompanied by a comparatively much smaller increase of the steady state photocurrent response which can be reconciled with a decrease in the mobility (μ) of holes. The decrease of μ is supported from an unusual increase of the Y/μ ratio of the out-of-phase modulated photocurrent (Y) signal to the mobility under light excitation. It is proposed that the mobile holes, which are generated from the dissociation of the light-created excitons more likely near the pentacene-substrate interface by electron trapping, populate grain boundaries charging them and producing a downward band bending. As a result, potential energy barriers are build up which limit the transport of holes interacting through trapping-detrapping with deep partially occupied traps in the charged grain boundaries. On the other hand, the transport of holes interacting through trapping-detrapping with empty traps is found unaffected.

  5. Designing thiophene-based azomethine oligomers with tailored properties: Self-assembly and charge carrier mobility

    DEFF Research Database (Denmark)

    Kiriy, N.; Bocharova, V.; Kiriy, A.

    2004-01-01

    This paper describes synthesis and characterization of two thiophene-based azomethines designed to optimize solubility, self-assembly, and charge carrier mobility. We found that incorporation of azomethine and amide moieties in the alpha,omega-position, and hexyl chains in the beta-position of th...... with the mobilities of the best organic semiconductors. All these significant differences in properties of related compounds can be attributed to the hydrogen bonding between QT-amide molecules responsible for the observed self-assembly....

  6. Estimation of carrier mobility at organic semiconductor/insulator interface using an asymmetric capacitive test structure

    Directory of Open Access Journals (Sweden)

    Rajesh Agarwal

    2016-04-01

    Full Text Available Mobility of carriers at the organic/insulator interface is crucial to the performance of organic thin film transistors. The present work describes estimation of mobility using admittance measurements performed on an asymmetric capacitive test structure. Besides the advantage of simplicity, it is shown that at low frequencies, the measured capacitance comes from a large area of channel making the capacitance-voltage characteristics insensitive to contact resistances. 2-D numerical simulation and experimental results obtained with Pentacene/Poly(4-vinyphenol system are presented to illustrate the operation and advantages of the proposed technique.

  7. Observation of disorder effects on charged carrier mobility in triphenylene-based discotic materials

    International Nuclear Information System (INIS)

    Zhang Chunxiu; He, Zhiqun; Mao Huaxiang; Wang Junjie; Wang Dongdong; Wang Yongsheng; Li Zhongxiao; Pu Jialing

    2007-01-01

    A discotic 2,6,10-trihydroxy-3,7,11-tripentyloxytriphenylene material and a triphenylene-based hyperbranched macromolecule were synthesized, in which the latter was prepared from AB m molecules in a one-pot reaction. Adipic chloride and butyryl chloride were chosen as terminal groups to the 2,6,10-trihydroxy-3,7,11-tripentyloxytriphenylene. Mesophase and their structural orders were determined using a polarized optical microscope and a differential scanning calorimeter. Carrier mobilities of the pure and composite materials were measured via a time-of-flight method. A change in carrier mobility on the morphology of the materials was further discussed. It was found that degree of crystallization was the key for a discotic triphenylene material to possess charge-transporting properties, no matter it is ordered or disordered

  8. Modelling of the charge carrier mobility in disordered linear polymer materials

    Czech Academy of Sciences Publication Activity Database

    Toman, Petr; Menšík, Miroslav; Bartkowiak, W.; Pfleger, Jiří

    2017-01-01

    Roč. 19, č. 11 (2017), s. 7760-7771 ISSN 1463-9076 R&D Projects: GA ČR(CZ) GA15-05095S Grant - others:AV ČR(CZ) M200501204 Program:M Institutional support: RVO:61389013 Keywords : charge carrier mobility * conjugated polymer * charge transport modelling Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 4.123, year: 2016

  9. Large Modulation of Charge Carrier Mobility in Doped Nanoporous Organic Transistors

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Fengjiao [Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, 600 S. Mathews Ave. Urbana IL 61801 USA; Dai, Xiaojuan [Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 P. R. China; Zhu, Weikun [Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, 600 S. Mathews Ave. Urbana IL 61801 USA; Chung, Hyunjoong [Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, 600 S. Mathews Ave. Urbana IL 61801 USA; Diao, Ying [Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, 600 S. Mathews Ave. Urbana IL 61801 USA

    2017-05-10

    Molecular doping of organic electronics has shown promise to sensitively modulate important device metrics. One critical challenge is the disruption of structure order upon doping of highly crystalline organic semiconductors, which significantly reduces the charge carrier mobility. This paper demonstrates a new method to achieve large modulation of charge carrier mobility via channel doping without disrupting the molecular ordering. Central to the method is the introduction of nanopores into the organic semiconductor thin films via a simple and robust templated meniscus-guided coating method. Using this method, the charge carrier mobility of C8-benzothieno[3,2-b]benzothiophene transistors is boosted by almost sevenfold. This paper further demonstrates enhanced electron transport by close to an order of magnitude in a diketopyrrolopyrrole-based donor–acceptor polymer. Combining spectroscopic measurements, density functional theory calculations, and electrical characterizations, the doping mechanism is identified as partial-charge-transfer induced trap filling. The nanopores serve to enhance the dopant/organic semiconductor charge transfer reaction by exposing the π-electrons to the pore wall.

  10. Field effect measurements on charge carrier mobilities in various polymer-fullerene blend compositions

    International Nuclear Information System (INIS)

    Hauff, Elizabeth von; Parisi, Juergen; Dyakonov, Vladimir

    2006-01-01

    In this study we investigated materials typically used in polymer photovoltaics. Field effect measurements were performed in order to determine the hole mobilities in the conjugated polymer poly(3-hexylthiophene) (P3HT) and the electron mobilities in the methanofullerene[6,6]-phenyl C 61 -butyric acid methyl ester (PCBM), and, particularly, in the polymer-fullerene composite blends. Regarding the pure films, electron mobilities in PCBM were found to be in the 10 -2 cm 2 /Vs range, and hole mobilities in P3HT were found to be in the 10 -3 cm2/Vs range. In the PCBM:P3HT blends, it was found that varying the PCBM content in PCBM:P3HT blends led to a steep increase in electron mobility with increasing PCBM content, while the hole mobility was found to slightly decrease with the increasing PCBM concentration. In 2:1 PCBM:P3HT tempered blends, the charge carrier mobilities were found to be roughly balanced, at 10 -3 cm 2 /Vs. For improved electron transport in the blends, tempering was found to be crucial

  11. Structure, ionic Conductivity and mobile Carrier Density in Fast Ionic Conducting Chalcogenide Glasses

    International Nuclear Information System (INIS)

    Wenlong Yao

    2006-01-01

    This thesis consists of six sections. The first section gives the basic research background on the ionic conduction mechanism in glass, polarization in the glass, and the method of determining the mobile carrier density in glass. The proposed work is also included in this section. The second section is a paper that characterizes the structure of MI + M 2 S + (0.1 Ga 2 S 3 + 0.9 GeS 2 ) (M = Li, Na, K and Cs) glasses using Raman and IR spectroscopy. Since the ionic radius plays an important role in determining the ionic conductivity in glasses, the glass forming range for the addition of different alkalis into the basic glass forming system 0.1 Ga 2 S 3 + 0.9 GeS 2 was studied. The study found that the change of the alkali radius for the same nominal composition causes significant structure change to the glasses. The third section is a paper that investigates the ionic conductivity of MI + M 2 S + (0.1Ga 2 S 3 + 0.9 GeS 2 ) (M = Li, Na, K and Cs) glasses system. Corresponding to the compositional changes in these fast ionic conducting glasses, the ionic conductivity shows changes due to the induced structural changes. The ionic radius effect on the ionic conductivity in these glasses was investigated. The fourth section is a paper that examines the mobile carrier density based upon the measurements of space charge polarization. For the first time, the charge carrier number density in fast ionic conducting chalcogenide glasses was determined. The experimental impedance data were fitted using equivalent circuits and the obtained parameters were used to determine the mobile carrier density. The influence of mobile carrier density and mobility on the ionic conductivity was separated. The fifth section is a paper that studies the structures of low-alkali-content Na 2 S + B 2 S 3 (x (le) 0.2) glasses by neutron and synchrotron x-ray diffraction. Similar results were obtained both in neutron and synchrotron x-ray diffraction experiments. The results provide direct

  12. Structure, ionic conductivity and mobile carrier density in fast ionic conducting chalcogenide glasses

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Wenlong [Iowa State Univ., Ames, IA (United States)

    2006-01-01

    This thesis consists of six sections. The first section gives the basic research background on the ionic conduction mechanism in glass, polarization in the glass, and the method of determining the mobile carrier density in glass. The proposed work is also included in this section. The second section is a paper that characterizes the structure of MI + M2S + (0.1 Ga2S3 + 0.9 GeS2) (M = Li, Na, K and Cs) glasses using Raman and IR spectroscopy. Since the ionic radius plays an important role in determining the ionic conductivity in glasses, the glass forming range for the addition of different alkalis into the basic glass forming system 0.1 Ga2S3 + 0.9 GeS2 was studied. The study found that the change of the alkali radius for the same nominal composition causes significant structure change to the glasses. The third section is a paper that investigates the ionic conductivity of MI + M2S + (0.1Ga2S3 + 0.9 GeS2) (M = Li, Na, K and Cs) glasses system. Corresponding to the compositional changes in these fast ionic conducting glasses, the ionic conductivity shows changes due to the induced structural changes. The ionic radius effect on the ionic conductivity in these glasses was investigated. The fourth section is a paper that examines the mobile carrier density based upon the measurements of space charge polarization. For the first time, the charge carrier number density in fast ionic conducting chalcogenide glasses was determined. The experimental impedance data were fitted using equivalent circuits and the obtained parameters were used to determine the mobile carrier density. The influence of mobile carrier density and mobility on the ionic conductivity was separated. The fifth section is a paper that studies the structures of low-alkali-content Na2S + B2S3 (x ≤ 0.2) glasses by neutron and synchrotron x-ray diffraction

  13. Measuring the lateral charge-carrier mobility in metal-insulator-semiconductor capacitors via Kelvin-probe.

    Science.gov (United States)

    Milotti, Valeria; Pietsch, Manuel; Strunk, Karl-Philipp; Melzer, Christian

    2018-01-01

    We report a Kelvin-probe method to investigate the lateral charge-transport properties of semiconductors, most notably the charge-carrier mobility. The method is based on successive charging and discharging of a pre-biased metal-insulator-semiconductor stack by an alternating voltage applied to one edge of a laterally confined semiconductor layer. The charge carriers spreading along the insulator-semiconductor interface are directly measured by a Kelvin-probe, following the time evolution of the surface potential. A model is presented, describing the device response for arbitrary applied biases allowing the extraction of the lateral charge-carrier mobility from experimentally measured surface potentials. The method is tested using the organic semiconductor poly(3-hexylthiophene), and the extracted mobilities are validated through current voltage measurements on respective field-effect transistors. Our widely applicable approach enables robust measurements of the lateral charge-carrier mobility in semiconductors with weak impact from the utilized contact materials.

  14. Measuring the lateral charge-carrier mobility in metal-insulator-semiconductor capacitors via Kelvin-probe

    Science.gov (United States)

    Milotti, Valeria; Pietsch, Manuel; Strunk, Karl-Philipp; Melzer, Christian

    2018-01-01

    We report a Kelvin-probe method to investigate the lateral charge-transport properties of semiconductors, most notably the charge-carrier mobility. The method is based on successive charging and discharging of a pre-biased metal-insulator-semiconductor stack by an alternating voltage applied to one edge of a laterally confined semiconductor layer. The charge carriers spreading along the insulator-semiconductor interface are directly measured by a Kelvin-probe, following the time evolution of the surface potential. A model is presented, describing the device response for arbitrary applied biases allowing the extraction of the lateral charge-carrier mobility from experimentally measured surface potentials. The method is tested using the organic semiconductor poly(3-hexylthiophene), and the extracted mobilities are validated through current voltage measurements on respective field-effect transistors. Our widely applicable approach enables robust measurements of the lateral charge-carrier mobility in semiconductors with weak impact from the utilized contact materials.

  15. Boost Up Carrier Mobility for Ferroelectric Organic Transistor Memory via Buffering Interfacial Polarization Fluctuation

    Science.gov (United States)

    Sun, Huabin; Wang, Qijing; Li, Yun; Lin, Yen-Fu; Wang, Yu; Yin, Yao; Xu, Yong; Liu, Chuan; Tsukagoshi, Kazuhito; Pan, Lijia; Wang, Xizhang; Hu, Zheng; Shi, Yi

    2014-11-01

    Ferroelectric organic field-effect transistors (Fe-OFETs) have been attractive for a variety of non-volatile memory device applications. One of the critical issues of Fe-OFETs is the improvement of carrier mobility in semiconducting channels. In this article, we propose a novel interfacial buffering method that inserts an ultrathin poly(methyl methacrylate) (PMMA) between ferroelectric polymer and organic semiconductor layers. A high field-effect mobility (μFET) up to 4.6 cm2 V-1 s-1 is obtained. Subsequently, the programming process in our Fe-OFETs is mainly dominated by the switching between two ferroelectric polarizations rather than by the mobility-determined charge accumulation at the channel. Thus, the ``reading'' and ``programming'' speeds are significantly improved. Investigations show that the polarization fluctuation at semiconductor/insulator interfaces, which affect the charge transport in conducting channels, can be suppressed effectively using our method.

  16. MODELLING OF CHARGE CARRIER MOBILITY FOR TRANSPORT BETWEEN ELASTIC POLYACETYLENE-LIKE POLYMER NANORODS

    Directory of Open Access Journals (Sweden)

    M. Mensik

    2017-03-01

    Full Text Available A quantum model solving the charge carrier mobility between polyacetylene-like polymer nanorods is presented. The model assumes: a Quantum mechanical calculation of hole on-chain delocalization involving electron-phonon coupling leading to the Peierls instability, b Hybridization coupling between the polymer backbone and side-groups (or environmental states, which act as hole traps, and c Semiclassical description of the inter-chain hole transfer in an applied voltage based on Marcus theory. We have found that mobility resonantly depends on the hybridization coupling between polymer and linked groups. We observed also non-trivial mobility dependences on the difference of energies of the highest occupied molecular orbitals localized on the polymer backbone and side-groups, respectively, and hole concentration. Those findings are important for optimization of hybrid opto-electronic devices.

  17. Accurate Extraction of Charge Carrier Mobility in 4-Probe Field-Effect Transistors

    KAUST Repository

    Choi, Hyun Ho; Rodionov, Yaroslav I.; Paterson, Alexandra F.; Panidi, Julianna; Saranin, Danila; Kharlamov, Nikolai; Didenko, Sergei I.; Anthopoulos, Thomas D.; Cho, Kilwon; Podzorov, Vitaly

    2018-01-01

    Charge carrier mobility is an important characteristic of organic field-effect transistors (OFETs) and other semiconductor devices. However, accurate mobility determination in FETs is frequently compromised by issues related to Schottky-barrier contact resistance, that can be efficiently addressed by measurements in 4-probe/Hall-bar contact geometry. Here, it is shown that this technique, widely used in materials science, can still lead to significant mobility overestimation due to longitudinal channel shunting caused by voltage probes in 4-probe structures. This effect is investigated numerically and experimentally in specially designed multiterminal OFETs based on optimized novel organic-semiconductor blends and bulk single crystals. Numerical simulations reveal that 4-probe FETs with long but narrow channels and wide voltage probes are especially prone to channel shunting, that can lead to mobilities overestimated by as much as 350%. In addition, the first Hall effect measurements in blended OFETs are reported and how Hall mobility can be affected by channel shunting is shown. As a solution to this problem, a numerical correction factor is introduced that can be used to obtain much more accurate experimental mobilities. This methodology is relevant to characterization of a variety of materials, including organic semiconductors, inorganic oxides, monolayer materials, as well as carbon nanotube and semiconductor nanocrystal arrays.

  18. Accurate Extraction of Charge Carrier Mobility in 4-Probe Field-Effect Transistors

    KAUST Repository

    Choi, Hyun Ho

    2018-04-30

    Charge carrier mobility is an important characteristic of organic field-effect transistors (OFETs) and other semiconductor devices. However, accurate mobility determination in FETs is frequently compromised by issues related to Schottky-barrier contact resistance, that can be efficiently addressed by measurements in 4-probe/Hall-bar contact geometry. Here, it is shown that this technique, widely used in materials science, can still lead to significant mobility overestimation due to longitudinal channel shunting caused by voltage probes in 4-probe structures. This effect is investigated numerically and experimentally in specially designed multiterminal OFETs based on optimized novel organic-semiconductor blends and bulk single crystals. Numerical simulations reveal that 4-probe FETs with long but narrow channels and wide voltage probes are especially prone to channel shunting, that can lead to mobilities overestimated by as much as 350%. In addition, the first Hall effect measurements in blended OFETs are reported and how Hall mobility can be affected by channel shunting is shown. As a solution to this problem, a numerical correction factor is introduced that can be used to obtain much more accurate experimental mobilities. This methodology is relevant to characterization of a variety of materials, including organic semiconductors, inorganic oxides, monolayer materials, as well as carbon nanotube and semiconductor nanocrystal arrays.

  19. Charge carrier mobility and electronic properties of Al(Op3: impact of excimer formation

    Directory of Open Access Journals (Sweden)

    Andrea Magri

    2015-05-01

    Full Text Available We have studied the electronic properties and the charge carrier mobility of the organic semiconductor tris(1-oxo-1H-phenalen-9-olatealuminium(III (Al(Op3 both experimentally and theoretically. We experimentally estimated the HOMO and LUMO energy levels to be −5.93 and −3.26 eV, respectively, which were close to the corresponding calculated values. Al(Op3 was successfully evaporated onto quartz substrates and was clearly identified in the absorption spectra of both the solution and the thin film. A structured steady state fluorescence emission was detected in solution, whereas a broad, red-shifted emission was observed in the thin film. This indicates the formation of excimers in the solid state, which is crucial for the transport properties. The incorporation of Al(Op3 into organic thin film transistors (TFTs was performed in order to measure the charge carrier mobility. The experimental setup detected no electron mobility, while a hole mobility between 0.6 × 10−6 and 2.1 × 10−6 cm2·V−1·s−1 was measured. Theoretical simulations, on the other hand, predicted an electron mobility of 9.5 × 10−6 cm2·V−1·s−1 and a hole mobility of 1.4 × 10−4 cm2·V−1·s−1. The theoretical simulation for the hole mobility predicted an approximately one order of magnitude higher hole mobility than was observed in the experiment, which is considered to be in good agreement. The result for the electron mobility was, on the other hand, unexpected, as both the calculated electron mobility and chemical common sense (based on the capability of extended aromatic structures to efficiently accept and delocalize additional electrons suggest more robust electron charge transport properties. This discrepancy is explained by the excimer formation, whose inclusion in the multiscale simulation workflow is expected to bring the theoretical simulation and experiment into agreement.

  20. Electronic characteristics of p-type transparent SnO monolayer with high carrier mobility

    International Nuclear Information System (INIS)

    Du, Juan; Xia, Congxin; Liu, Yaming; Li, Xueping; Peng, Yuting; Wei, Shuyi

    2017-01-01

    Graphical abstract: SnO monolayer is a p-type transparent semiconducting oxide with high hole mobility (∼641 cm 2 V −1 s −1 ), which is much higher than that of MoS 2 monolayer, which indicate that it can be a promising candidate for high-performance nanoelectronic devices. Display Omitted - Highlights: • SnO monolayer is a p-type transparent semiconducting oxide. • The transparent properties can be still maintained under the strain 8%. • It has a high hole mobility (∼641 cm 2 V −1 s −1 ), which is higher than that of MoS 2 monolayer. - Abstract: More recently, two-dimensional (2D) SnO nanosheets are attaching great attention due to its excellent carrier mobility and transparent characteristics. Here, the stability, electronic structures and carrier mobility of SnO monolayer are investigated by using first-principles calculations. The calculations of the phonon dispersion spectra indicate that SnO monolayer is dynamically stable. Moreover, the band gap values are decreased from 3.93 eV to 2.75 eV when the tensile strain is applied from 0% to 12%. Interestingly, SnO monolayer is a p-type transparent semiconducting oxide with hole mobility of 641 cm 2 V −1 s −1 , which is much higher than that of MoS 2 monolayer. These findings make SnO monolayer becomes a promising 2D material for applications in nanoelectronic devices.

  1. Electronic characteristics of p-type transparent SnO monolayer with high carrier mobility

    Energy Technology Data Exchange (ETDEWEB)

    Du, Juan [College of Physics and Materials Science, Henan Normal University, Xinxiang, Henan 453007 (China); Xia, Congxin, E-mail: xiacongxin@htu.edu.cn [College of Physics and Materials Science, Henan Normal University, Xinxiang, Henan 453007 (China); Liu, Yaming [Henan Institute of Science and Technology, Xinxiang 453003 (China); Li, Xueping [College of Physics and Materials Science, Henan Normal University, Xinxiang, Henan 453007 (China); Peng, Yuting [Department of Physics, University of Texas at Arlington, TX 76019 (United States); Wei, Shuyi [College of Physics and Materials Science, Henan Normal University, Xinxiang, Henan 453007 (China)

    2017-04-15

    Graphical abstract: SnO monolayer is a p-type transparent semiconducting oxide with high hole mobility (∼641 cm{sup 2} V{sup −1} s{sup −1}), which is much higher than that of MoS{sub 2} monolayer, which indicate that it can be a promising candidate for high-performance nanoelectronic devices. Display Omitted - Highlights: • SnO monolayer is a p-type transparent semiconducting oxide. • The transparent properties can be still maintained under the strain 8%. • It has a high hole mobility (∼641 cm{sup 2} V{sup −1} s{sup −1}), which is higher than that of MoS{sub 2} monolayer. - Abstract: More recently, two-dimensional (2D) SnO nanosheets are attaching great attention due to its excellent carrier mobility and transparent characteristics. Here, the stability, electronic structures and carrier mobility of SnO monolayer are investigated by using first-principles calculations. The calculations of the phonon dispersion spectra indicate that SnO monolayer is dynamically stable. Moreover, the band gap values are decreased from 3.93 eV to 2.75 eV when the tensile strain is applied from 0% to 12%. Interestingly, SnO monolayer is a p-type transparent semiconducting oxide with hole mobility of 641 cm{sup 2} V{sup −1} s{sup −1}, which is much higher than that of MoS{sub 2} monolayer. These findings make SnO monolayer becomes a promising 2D material for applications in nanoelectronic devices.

  2. Time-dependent mobility and recombination of the photoinduced charge carriers in conjugated polymer/fullerene bulk heterojunction solar cells

    Science.gov (United States)

    Mozer, A. J.; Dennler, G.; Sariciftci, N. S.; Westerling, M.; Pivrikas, A.; Österbacka, R.; Juška, G.

    2005-07-01

    Time-dependent mobility and recombination in the blend of poly[2-methoxy-5-(3,7-dimethyloctyloxy)-phenylene vinylene] (MDMO-PPV) and 1-(3-methoxycarbonyl)propyl-1-phenyl-(6,6)- C61 (PCBM) is studied simultaneously using the photoinduced charge carrier extraction by linearly increasing voltage technique. The charge carriers are photogenerated by a strongly absorbed, 3 ns laser flash, and extracted by the application of a reverse bias voltage pulse after an adjustable delay time (tdel) . It is found that the mobility of the extracted charge carriers decreases with increasing delay time, especially shortly after photoexcitation. The time-dependent mobility μ(t) is attributed to the energy relaxation of the charge carriers towards the tail states of the density of states distribution. A model based on a dispersive bimolecular recombination is formulated, which properly describes the concentration decay of the extracted charge carriers at all measured temperatures and concentrations. The calculated bimolecular recombination coefficient β(t) is also found to be time-dependent exhibiting a power law dependence as β(t)=β0t-(1-γ) with increasing slope (1-γ) with decreasing temperatures. The temperature dependence study reveals that both the mobility and recombination of the photogenerated charge carriers are thermally activated processes with activation energy in the range of 0.1 eV. Finally, the direct comparison of μ(t) and β(t) shows that the recombination of the long-lived charge carriers is controlled by diffusion.

  3. Towards high charge carrier mobilities by rational design of organic semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Andrienko, Denis; Ruehle, Victor; Baumeier, Bjoern; Vehoff, Thorsten; Lukyanov, Alexander; Kremer, Kurt [Max Planck Institute for Polymer Research, Mainz (Germany); Marcon, Valentina [Technische Universitaet Darmstadt (Germany); Kirkpatrick, James; Nelson, Jenny [Imperial College London (United Kingdom); Lennartz, Christian [BASF AG, Ludwigshafen (Germany)

    2010-07-01

    The role of material morphology on charge carrier mobility in partially disordered organic semiconductors is discussed for several classes of materials: derivatives of hexabenzocoronenens, perylenediimides, triangularly-shaped polyaromatic hydrocarbons, and Alq{sub 3}. Simulations are performed using a package developed by Imperial College, London and Max Planck Institute for Polymer Research, Mainz (votca.org). This package combines several techniques into one scheme: quantum chemical methods for the calculation of molecular electronic structures and reorganization energies; molecular dynamics and systematic coarse-graining approaches for simulation of self-assembly and relative positions and orientations of molecules on large scales; kinetic Monte Carlo and master equation for studies of charge transport.

  4. Mobility enhancements for LTE-Advanced Multilayer Networks with Inter-Site Carrier Aggregation

    DEFF Research Database (Denmark)

    Pedersen, Klaus I.; Michaelsen, Per Henrik; Rosa, Claudio

    2013-01-01

    In this article we first summarize some of the most recent HetNet mobility studies for LTE-Advanced, and use these to highlight the challenges that should be further addressed in theresearch community. A state-of-the-art HetNet scenario with macros and small cells deployed on different carriers...... decide small cell addition, removal, and change without any explicit signaling of Measurement events to the network or any signaling of hand-over commands from the network. Hence, the proposed solution effectively offloads the network from having to perform frequent small cell handoff decisions...

  5. Modelling of charge carrier mobility for transport between elastic polyacetylene-like polymer nanorods

    Czech Academy of Sciences Publication Activity Database

    Menšík, Miroslav; Sun, S. J.; Toman, Petr; Král, Karel

    2017-01-01

    Roč. 61, č. 2 (2017), s. 127-135 ISSN 0862-5468 R&D Projects: GA MŠk(CZ) LD14011; GA ČR(CZ) GA15-05095S Grant - others:European Commission(XE) COST Action MP1202 HINT; AV ČR(CZ) KONNECT-007 Program:Bilaterální spolupráce Institutional support: RVO:61389013 ; RVO:68378271 Keywords : charge carrier mobility * polymers * electron-phonon coupling Subject RIV: CF - Physical ; Theoretical Chemistry; CF - Physical ; Theoretical Chemistry (FZU-D) OBOR OECD: Physical chemistry; Physical chemistry (FZU-D) Impact factor: 0.439, year: 2016

  6. A new approach to calculate charge carrier transport mobility in organic molecular crystals from imaginary time path integral simulations

    International Nuclear Information System (INIS)

    Song, Linze; Shi, Qiang

    2015-01-01

    We present a new non-perturbative method to calculate the charge carrier mobility using the imaginary time path integral approach, which is based on the Kubo formula for the conductivity, and a saddle point approximation to perform the analytic continuation. The new method is first tested using a benchmark calculation from the numerical exact hierarchical equations of motion method. Imaginary time path integral Monte Carlo simulations are then performed to explore the temperature dependence of charge carrier delocalization and mobility in organic molecular crystals (OMCs) within the Holstein and Holstein-Peierls models. The effects of nonlocal electron-phonon interaction on mobility in different charge transport regimes are also investigated

  7. On the role of local charge carrier mobility in the charge separation mechanism of organic photovoltaics.

    Science.gov (United States)

    Yoshikawa, Saya; Saeki, Akinori; Saito, Masahiko; Osaka, Itaru; Seki, Shu

    2015-07-21

    Although the charge separation (CS) and transport processes that compete with geminate and non-geminate recombination are commonly regarded as the governing factors of organic photovoltaic (OPV) efficiency, the details of the CS mechanism remain largely unexplored. Here we provide a systematic investigation on the role of local charge carrier mobility in bulk heterojunction films of ten different low-bandgap polymers and polythiophene analogues blended with methanofullerene (PCBM). By correlating with the OPV performances, we demonstrated that the local mobility of the blend measured by time-resolved microwave conductivity is more important for the OPV output than those of the pure polymers. Furthermore, the results revealed two separate trends for crystalline and semi-crystalline polymers. This work offers guidance in the design of high-performance organic solar cells.

  8. Strain engineering on electronic structure and carrier mobility in monolayer GeP3

    Science.gov (United States)

    Zeng, Bowen; Long, Mengqiu; Zhang, Xiaojiao; Dong, Yulan; Li, Mingjun; Yi, Yougen; Duan, Haiming

    2018-06-01

    Using density functional theory coupled with the Boltzmann transport equation with relaxation time approximation, we have studied the strain effect on the electronic structure and carrier mobility of two-dimensional monolayer GeP3. We find that the energies of valence band maximum and conduction band minimum are nearly linearly shifted with a biaxial strain in the range of  ‑4% to 6%, and the band structure experiences a remarkable transition from semiconductor to metal with the appropriate compression (‑5% strain). Under biaxial strain, the mobility of the electron and hole in monolayer GeP3 reduces and increases by more than one order of magnitude, respectively. It is suggested that it is possible to perform successive transitions from an n-type semiconductor (‑4% strain) to a good performance p-semiconductor (+6% strain) by applying strain in monolayer GeP3, which is potentially useful for flexible electronics and nanosized mechanical sensors.

  9. Diverse carrier mobility of monolayer BNC x : a combined density functional theory and Boltzmann transport theory study.

    Science.gov (United States)

    Wu, Tao; Deng, Kaiming; Deng, Weiqiao; Lu, Ruifeng

    2017-10-19

    BNC x monolayer as a kind of two-dimensional material has numerous chemical atomic ratios and arrangements with different electronic structures. Via calculations on the basis of density functional theory and Boltzmann transport theory under deformation potential approximation, the band structures and carrier mobilities of BNC x (x  =  1,2,3,4) nanosheets are systematically investigated. The calculated results show that BNC 2 -1 is a material with very small band gap (0.02 eV) among all the structures while other BNC x monolayers are semiconductors with band gap ranging from 0.51 eV to 1.32 eV. The carrier mobility of BNC x varies considerably from tens to millions of cm 2 V -1 s -1 . For BNC 2 -1, the hole mobility and electron mobility along both x and y directions can reach 10 5 orders of magnitude, which is similar to the carrier mobility of graphene. Besides, all studied BNC x monolayers obviously have anisotropic hole mobility and electron mobility. In particular, for semiconductor BNC 4 , its hole mobility along the y direction and electron mobility along the x direction unexpectedly reach 10 6 orders of magnitude, even higher than that of graphene. Our findings suggest that BNC x layered materials with the proper ratio and arrangement of carbon atoms will possess desirable charge transport properties, exhibiting potential applications in nanoelectronic devices.

  10. Carrier mobility in mesoscale heterogeneous organic materials: Effects of crystallinity and anisotropy on efficient charge transport

    Science.gov (United States)

    Kobayashi, Hajime; Shirasawa, Raku; Nakamoto, Mitsunori; Hattori, Shinnosuke; Tomiya, Shigetaka

    2017-07-01

    Charge transport in the mesoscale bulk heterojunctions (BHJs) of organic photovoltaic devices (OPVs) is studied using multiscale simulations in combination with molecular dynamics, the density functional theory, the molecular-level kinetic Monte Carlo (kMC) method, and the coarse-grained kMC method, which was developed to estimate mesoscale carrier mobility. The effects of the degree of crystallinity and the anisotropy of the conductivity of donors on hole mobility are studied for BHJ structures that consist of crystalline and amorphous pentacene grains that act as donors and amorphous C60 grains that act as acceptors. We find that the hole mobility varies dramatically with the degree of crystallinity of pentacene because it is largely restricted by a low-mobility amorphous region that occurs in the hole transport network. It was also found that the percolation threshold of crystalline pentacene is relatively high at approximately 0.6. This high percolation threshold is attributed to the 2D-like conductivity of crystalline pentacene, and the threshold is greatly improved to a value of approximately 0.3 using 3D-like conductive donors. We propose essential guidelines to show that it is critical to increase the degree of crystallinity and develop 3D conductive donors for efficient hole transport through percolative networks in the BHJs of OPVs.

  11. In-plane heterostructures of Sb/Bi with high carrier mobility

    Science.gov (United States)

    Zhao, Pei; Wei, Wei; Sun, Qilong; Yu, Lin; Huang, Baibiao; Dai, Ying

    2017-06-01

    In-plane two-dimensional (2D) heterostructures have been attracting public attention due to their distinctive properties. However, the pristine materials that can form in-plane heterostructures are reported only for graphene, hexagonal BN, transition-metal dichalcogenides. It will be of great significance to explore more suitable 2D materials for constructing such ingenious heterostructures. Here, we demonstrate two types of novel seamless in-plane heterostructures combined by pristine Sb and Bi monolayers by means of first-principle approach based on density functional theory. Our results indicate that external strain can serve as an effective strategy for bandgap engineering, and the transition from semiconductor to metal occurs when a compressive strain of -8% is applied. In addition, the designed heterostructures possess direct band gaps with high carrier mobility (˜4000 cm2 V-1 s-1). And the mobility of electrons and holes have huge disparity along the direction perpendicular to the interface of Sb/Bi in-plane heterostructures. It is favorable for carriers to separate spatially. Finally, we find that the band edge positions of Sb/Bi in-plane heterostructures can meet the reduction potential of hydrogen generation in photocatalysis. Our results not only offer alternative materials to construct versatile in-plane heterostructures, but also highlight the applications of 2D in-plane heterostructures in diverse nanodevices and photocatalysis.

  12. Balance the Carrier Mobility To Achieve High Performance Exciplex OLED Using a Triazine-Based Acceptor.

    Science.gov (United States)

    Hung, Wen-Yi; Chiang, Pin-Yi; Lin, Shih-Wei; Tang, Wei-Chieh; Chen, Yi-Ting; Liu, Shih-Hung; Chou, Pi-Tai; Hung, Yi-Tzu; Wong, Ken-Tsung

    2016-02-01

    A star-shaped 1,3,5-triazine/cyano hybrid molecule CN-T2T was designed and synthesized as a new electron acceptor for efficient exciplex-based OLED emitter by mixing with a suitable electron donor (Tris-PCz). The CN-T2T/Tris-PCz exciplex emission shows a high ΦPL of 0.53 and a small ΔET-S = -0.59 kcal/mol, affording intrinsically efficient fluorescence and highly efficient exciton up-conversion. The large energy level offsets between Tris-PCz and CN-T2T and the balanced hole and electron mobility of Tris-PCz and CN-T2T, respectively, ensuring sufficient carrier density accumulated in the interface for efficient generation of exciplex excitons. Employing a facile device structure composed as ITO/4% ReO3:Tris-PCz (60 nm)/Tris-PCz (15 nm)/Tris-PCz:CN-T2T(1:1) (25 nm)/CN-T2T (50 nm)/Liq (0.5 nm)/Al (100 nm), in which the electron-hole capture is efficient without additional carrier injection barrier from donor (or acceptor) molecule and carriers mobilities are balanced in the emitting layer, leads to a highly efficient green exciplex OLED with external quantum efficiency (EQE) of 11.9%. The obtained EQE is 18% higher than that of a comparison device using an exciplex exhibiting a comparable ΦPL (0.50), in which TCTA shows similar energy levels but higher hole mobility as compared with Tris-PCz. Our results clearly indicate the significance of mobility balance in governing the efficiency of exciplex-based OLED. Exploiting the Tris-PCz:CN-T2T exciplex as the host, we further demonstrated highly efficient yellow and red fluorescent OLEDs by doping 1 wt % Rubrene and DCJTB as emitter, achieving high EQE of 6.9 and 9.7%, respectively.

  13. Introducing correlations into carrier transport simulations of disordered materials through seeded nucleation: impact on density of states, carrier mobility, and carrier statistics

    Science.gov (United States)

    Brown, J. S.; Shaheen, S. E.

    2018-04-01

    Disorder in organic semiconductors has made it challenging to achieve performance gains; this is a result of the many competing and often nuanced mechanisms effecting charge transport. In this article, we attempt to illuminate one of these mechanisms in the hopes of aiding experimentalists in exceeding current performance thresholds. Using a heuristic exponential function, energetic correlation has been added to the Gaussian disorder model (GDM). The new model is grounded in the concept that energetic correlations can arise in materials without strong dipoles or dopants, but may be a result of an incomplete crystal formation process. The proposed correlation has been used to explain the exponential tail states often observed in these materials; it is also better able to capture the carrier mobility field dependence, commonly known as the Poole-Frenkel dependence, when compared to the GDM. Investigation of simulated current transients shows that the exponential tail states do not necessitate Montroll and Scher fits. Montroll and Scher fits occur in the form of two distinct power law curves that share a common constant in their exponent; they are clearly observed as linear lines when the current transient is plotted using a log-log scale. Typically, these fits have been found appropriate for describing amorphous silicon and other disordered materials which display exponential tail states. Furthermore, we observe the proposed correlation function leads to domains of energetically similar sites separated by boundaries where the site energies exhibit stochastic deviation. These boundary sites are found to be the source of the extended exponential tail states, and are responsible for high charge visitation frequency, which may be associated with the molecular turnover number and ultimately the material stability.

  14. Growth Related Carrier Mobility Enhancement of Pentacene Thin-Film Transistors with High-k Oxide Gate Dielectric

    International Nuclear Information System (INIS)

    Ai-Fang, Yu; Qiong, Qi; Peng, Jiang; Chao, Jiang

    2009-01-01

    Carrier mobility enhancement from 0.09 to 0.59 cm 2 /Vs is achieved for pentacene-based thin-film transistors (TFTs) by modifying the HfO 2 gate dielectric with a polystyrene (PS) thin film. The improvement of the transistor's performance is found to be strongly related to the initial film morphologies of pentacene on the dielectrics. In contrast to the three-dimensional island-like growth mode on the HfO 2 surface, the Stranski-Krastanov growth mode on the smooth and nonpolar PS/HfO 2 surface is believed to be the origin of the excellent carrier mobility of the TFTs. A large well-connected first monolayer with fewer boundaries is formed via the Stranski–Krastanov growth mode, which facilitates a charge transport parallel to the substrate and promotes higher carrier mobility. (cross-disciplinary physics and related areas of science and technology)

  15. Side chain engineering of fused aromatic thienopyrazine based low band-gap polymers for enhanced charge carrier mobility

    KAUST Repository

    Mondal, Rajib

    2011-01-01

    A strategic side-chain engineering approach leads to the two orders of magnitude enhancement of charge carrier mobility in phenanthrene based fused aromatic thienopyrazine polymers. Hole carrier mobility up to 0.012 cm 2/Vs can be obtained in thin film transistor devices. Polymers were also utilized to fabricate bulk heterojunction photovoltaic devices and the maximum PCE obtained in these OPV\\'s was 1.15%. Most importantly, performances of the devices were correlated with thin morphological analysis performed by atomic force microscopy and grazing incidence X-ray scattering. © 2011 The Royal Society of Chemistry.

  16. The Complementary Relationship between Organizational Architecture and Organizational Agility An Empirical Study in Mobile Carriers of Erbil – Iraq

    OpenAIRE

    Laith Ali Yousif Al-Hakim; Thabit Hassan Thabit; Hamed Adel Abbas Al-Nasrawi

    2017-01-01

    The present research aims to investigate the relationship between organizational architecture and organizational agility in the mobile carriers of Erbil in Iraq. A questionnaire was conducted on mobile companies based on a random sampling technique. The results show there is a statistically significance and positive relation between organizational architecture and organizational agility. The results also indicated that organizational architecture has a statistically significant and direct pos...

  17. Multi-THz spectroscopy of mobile charge carriers in P3HT:PCBM on a sub-100 fs time scale

    DEFF Research Database (Denmark)

    Cooke, David G.; Krebs, Frederik C; Jepsen, Peter Uhd

    2013-01-01

    The dynamics of mobile charge carrier generation in polymer bulk heterojunction films is of vital importance to the development of more efficient organic photovoltaics. As with conventional semiconductors, the optical signatures of mobile carriers lie in the far-infrared (1-30 THz) although...

  18. 41 CFR 302-10.200 - What costs are allowable when a commercial carrier transports my mobile home overland or over water?

    Science.gov (United States)

    2010-07-01

    ... when a commercial carrier transports my mobile home overland or over water? 302-10.200 Section 302-10... carrier transports my mobile home overland or over water? Your agency will allow the following costs for... State or local law. (b) When transporting over water cost must include, but not limited to the cost of...

  19. The effects of inorganic surface treatments on photogenerated carrier mobility and lifetime in PbSe quantum dot thin films

    Energy Technology Data Exchange (ETDEWEB)

    Goodwin, E.D.; Straus, Daniel B. [Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104 (United States); Gaulding, E. Ashley [Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA 19104 (United States); Murray, Christopher B. [Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104 (United States); Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA 19104 (United States); Kagan, Cherie R., E-mail: kagan@seas.upenn.edu [Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104 (United States); Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA 19104 (United States); Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA 19104 (United States)

    2016-06-01

    Highlights: • Na{sub 2}Se and PbCl{sub 2} treatments modified the surface chemistry of PbSe quantum dots. • Excess Se (Pb) p-doped (n-doped) PbSe quantum dot thin films. • Carrier mobility and lifetime were studied using time-resolved microwave conductivity. • Mobility increased as the Fermi level approached the band edges. - Abstract: We used flash-photolysis, time-resolved microwave conductivity (TRMC) to probe the carrier mobility and lifetime in PbSe quantum dot (QD) thin films treated with solutions of the metal salts of Na{sub 2}Se and PbCl{sub 2}. The metal salt treatments tuned the Pb:Se stoichiometry and swept the Fermi energy throughout the QD thin film bandgap. A stoichiometric imbalance favoring excess Se heavily p-doped the QD thin film, shifted the Fermi energy toward the valence band, and yielded the highest TRMC mobility and lifetime. Introducing Pb first compensated the p-doping and shifted the Fermi level through mid-gap, decreasing the TRMC mobility. Further Pb addition created an excess of Pb, n-doped the QD thin film, moved the Fermi level to near the conduction band, and again increased the TRMC mobility. The increase in TRMC mobility as the Fermi energy was shifted toward the band edges by non-stoichiometry is consistent with the QD thin film density of states.

  20. Motion of a carrier with a mobile load along a rough inclined plane

    Science.gov (United States)

    Bilchenko, G. G.

    2018-03-01

    The mechanical system consisting of a carrier and a load is considered. The load can move respectively the carrier according to the preset given motion law. The carrier motion from rest caused the load motion is investigated. The carrier can move translationally along rectilinear trajectory along rough inclined plane. The trajectory is the line of the greatest descent. The axis of rectilinear channel along which the load moves is situated in vertical plane containing the carrier trajectory. The Coulomb model is taken to describe the friction forces on sloped plane. Differential equations of motion of carrier with load are obtained. The sufficient condition of the carrier motion without detachment from inclined plane is given. For two special cases of the channel installation angle and the plane inclination angle combination the motion types are described. The computation experiments results are presented: the carrier motions in the special cases are illustrated, the phase portraits for some types of motions are constructed.

  1. Enhancement of carrier mobility in all-inkjet-printed organic thin-film transistors using a blend of poly(3-hexylthiophene) and carbon nanoparticles

    International Nuclear Information System (INIS)

    Lin, Chih-Ting; Hsu, Chun-Hao; Chen, Iu-Ren; Lee, Chang-Hung; Wu, Wen-Jung

    2011-01-01

    To enhance the carrier mobility of all-inkjet-printed organic thin film transistors, we fabricated devices that incorporated poly(3-hexylthiophene) (P3HT) and carbon nanoparticles (CNPs). The fabricated devices had an on/off ratio of 10 4 , which is one order less than that of pristine organic thin-film transistors (OTFTs). The maximum carrier mobility as high as 0.053 cm 2 /V-s was achieved for a CNP/P3HT weight-weight ratio of 7/100. This degree of mobility is 10 times greater than average mobility of pristine P3HT-OTFTs. X-ray diffraction and scanning electron microscopy images reveal that the carrier mobility was enhanced by reducing the injection barrier and enhancing the carrier injection. This work demonstrates the feasibility of all-inkjet-printed OTFT technology.

  2. The Complementary Relationship between Organizational Architecture and Organizational Agility An Empirical Study in Mobile Carriers of Erbil – Iraq

    Directory of Open Access Journals (Sweden)

    Laith Ali Yousif Al-Hakim

    2017-02-01

    Full Text Available The present research aims to investigate the relationship between organizational architecture and organizational agility in the mobile carriers of Erbil in Iraq. A questionnaire was conducted on mobile companies based on a random sampling technique. The results show there is a statistically significance and positive relation between organizational architecture and organizational agility. The results also indicated that organizational architecture has a statistically significant and direct positive effect on organizational agility. Finally, the researchers draw an overall conclusion from the research as a whole.

  3. Two-frequency method for measuring Hall emf in high-resistive materials with charge-carrier low mobility

    International Nuclear Information System (INIS)

    Aleksandrov, A.L.; Vedeneev, A.S.; Gulyaev, I.B.; Zhdan, A.G.

    1982-01-01

    A facility for measuring Hall emf in high-resistive materials with low mobility of charge carriers by the two-frequency method using digital synchronous integration is described. The facility permits to detect the minimum Hall emf approxamatety equat to 5 μV at approximatety equal to 1 T Ohm of the investigated.sample resistance during the measuring time of approximately equal to 2000 s. Sensitivity by Hall mobility makes up >= 0.01 cm 2 /Vxs at the same measuring time. Measuring results of the Hall emf on GaAs monocrystals, CdSe films and island film of gold are presented

  4. High carrier mobility of CoPc wires based field-effect transistors using bi-layer gate dielectric

    Directory of Open Access Journals (Sweden)

    Murali Gedda

    2013-11-01

    Full Text Available Polyvinyl alcohol (PVA and anodized Al2O3 layers were used as bi-layer gate for the fabrication of cobalt phthalocyanine (CoPc wire base field-effect transistors (OFETs. CoPc wires were grown on SiO2 surfaces by organic vapor phase deposition method. These devices exhibit a field-effect carrier mobility (μEF value of 1.11 cm2/Vs. The high carrier mobility for CoPc molecules is attributed to the better capacitive coupling between the channel of CoPc wires and the gate through organic-inorganic dielectric layer. Our measurements also demonstrated the way to determine the thicknesses of the dielectric layers for a better process condition of OFETs.

  5. Measurement of the drift mobilities and the mobility-lifetime products of charge carriers in a CdZnTe crystal by using a transient pulse technique

    International Nuclear Information System (INIS)

    Cho, H Y; Kwon, Y K; Lee, C S; Lee, J H; Moon, J Y

    2011-01-01

    In this work we present results on the measurement of the drift mobility and the mobility-lifetime product of charge carriers in a 16-pixellated CdZnTe detector. For the determination of an interaction position based on the pulse rise-time method in a CZT detector, it is necessary to characterize the transport properties governed by drift mobility and lifetime for electrons and holes. In order to extract the transport properties of an electron and a hole, we bombarded 5.5-MeV alpha particles from a 241 Am source and 81-keV gamma rays emitted from a 133 Ba source on the negatively biased contact of the CZT detector. A time-of-flight (TOF) method was used to measure the electron drift mobility at room temperature whose value turned out to be 906.4 cm 2 /Vc s. With the Hecht's equation, the electron mobility-lifetime product was also determined from the bias-dependent alpha response and was equal to (9.88 ± 2.33) x 10 -3 cm 2 /V. On the other hand, the hole mobility-lifetime product was evaluated by a model based on the average charge collection efficiency which accounts for the absorption probability with a given photon energy. By using a single parameter fitting of the model, we obtained the hole mobility-lifetime product of (8.28 ± 0.17) x 10 -4 cm 2 /V.

  6. Improvement in carrier mobility and photovoltaic performance through random distribution of segments of linear and branched side chains

    Czech Academy of Sciences Publication Activity Database

    Egbe, D. A. M.; Adam, G.; Pivrikas, A.; Ramil, A. M.; Birckner, E.; Cimrová, Věra; Hoppe, H.; Sariciftci, N. S.

    2010-01-01

    Roč. 20, č. 43 (2010), s. 9726-9734 ISSN 0959-9428 R&D Projects: GA MŠk(CZ) 1M06031 Institutional research plan: CEZ:AV0Z40500505 Keywords : poly(p-phenylene-ethynylene)-alt-poly(p-phenylene-vinylene) * solar cells * charge carrier mobility Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 5.101, year: 2010

  7. Terahertz Conductivity within Colloidal CsPbBr3 Perovskite Nanocrystals: Remarkably High Carrier Mobilities and Large Diffusion Lengths.

    Science.gov (United States)

    Yettapu, Gurivi Reddy; Talukdar, Debnath; Sarkar, Sohini; Swarnkar, Abhishek; Nag, Angshuman; Ghosh, Prasenjit; Mandal, Pankaj

    2016-08-10

    Colloidal CsPbBr3 perovskite nanocrystals (NCs) have emerged as an excellent light emitting material in last one year. Using time domain and time-resolved THz spectroscopy and density functional theory based calculations, we establish 3-fold free carrier recombination mechanism, namely, nonradiative Auger, bimolecular electron-hole recombination, and inefficient trap-assisted recombination in 11 nm sized colloidal CsPbBr3 NCs. Our results confirm a negligible influence of surface defects in trapping charge carriers, which in turn results into desirable intrinsic transport properties, from the perspective of device applications, such as remarkably high carrier mobility (∼4500 cm(2) V(-1) s(-1)), large diffusion length (>9.2 μm), and high luminescence quantum yield (80%). Despite being solution processed and possessing a large surface to volume ratio, this combination of high carrier mobility and diffusion length, along with nearly ideal photoluminescence quantum yield, is unique compared to any other colloidal quantum dot system.

  8. On motions of a carrier with a mobile load along a rough inclined plane

    Science.gov (United States)

    Bilchenko, Grigory; Bilchenko, Grigory; Bilchenko, Nataly

    2018-05-01

    A mechanical system consisting of a carrier and a load is considered. The load can move respectively to the carrier according to a predetermined motion law. The carrier can move translationally along a rectilinear trajectory on a rough inclined plane. The trajectory is the line of the greatest descent. The axis of the rectilinear channel, along which the load moves, is located in a vertical plane passing through the trajectory of the carrier. The Coulomb dry friction model is applied for simulation the forces of resistance to the motion of the carrier from the side of the underlying inclined plane. The extreme value of plane inclination angle at which the carrier is at rest, when the load is stationary, is obtained by taking into account the frictional forces of sliding at rest. Differential equations of motion of a carrier with a load moving with respect to the carrier are obtained taking into account the requirement of motion of the carrier along an inclined plane without detachment. The determining relationships are given which made it possible to classify the types of carrier motion when the channel setting angle and the plane inclination angle are related by a certain inequality. The results of computational experiments are presented.

  9. Dependence of the carrier mobility and trapped charge limited conduction on silver nanoparticles embedment in doped polypyrrole nanostructures

    Science.gov (United States)

    Biswas, Swarup; Dutta, Bula; Bhattacharya, Subhratanu

    2013-10-01

    The present article demonstrates an intensive study upon the temperature dependent current density (J)-voltage (V) characteristics of moderately doped polypyrrole nanostructure and its silver nanoparticles incorporated nanocomposites. Analysis of the measured J-V characteristics of different synthesized nano-structured samples within a wide temperature range revealed that the electrical conduction behavior followed a trapped charge-limited conduction and a transition of charge transport mechanism from deep exponential trap limited conduction to shallow traps limited conduction had been occurred due to the incorporation of silver nanoparticles within the polypyrrole matrix. A direct evaluation of carrier mobility as a function of electric field and temperature from the measured J-V characteristics illustrates that the incorporation of silver nanoparticles within the polypyrrole matrix enhances the carrier mobility at a large extent by reducing the concentration of traps within the polypyrrole matrix. The calculated mobility is consistent with the Poole-Frenkel form for the electrical field up to a certain temperature range. The nonlinear low temperature dependency of mobility of all the nanostructured samples was explained by Mott variable range hopping conduction mechanisms. Quantitative information regarding the charge transport parameters obtained from the above study would help to extend optimization strategies for the fabrication of new organic semiconducting nano-structured devices.

  10. Use of natural gas, methanol, and ethanol fuel emulsions as environmentally friendly energy carriers for mobile heat power plants

    Science.gov (United States)

    Likhanov, V. A.; Lopatin, O. P.

    2017-12-01

    The need for using environmentally friendly energy carriers for mobile heat power plants (HPPs) is grounded. Ecologically friendly sources of energy, such as natural gas as well as renewable methyl and ethyl alcohols, are investigated. In order to develop, determine, and optimize the composition of environmentally friendly energy carriers for an HPP, the latter has been tested when working on diesel fuel (DF), compressed natural gas (CNG), and methanol and ethanol fuel emulsions (MFE, EFE). It has been experimentally established that, for the application of environmentally friendly energy carriers for a 4Ch 11.0/12.5 diesel engine of a mobile fuel and power plant, it is necessary to maintain the following ratio of components when working on CNG: 80% gas and 20% DF primer portion. When working on an alcohol mixture, emulsions of the following composition were used: 25% alcohol (methanol or ethanol), 0.5% detergent-dispersant additive succinimide C-5A, 7% water, and 67.5% DF. When this diesel passed from oil DF to environmentally friendly energy sources, it allowed for the reduction of the content of exhaust gases (EG) (1) when working on CNG with recirculation of exhaust gases (EGR) (recirculation was used to eliminate the increased amount of nitric oxides by using CNG): carbon black by 5.8 times, carbon dioxide by 45.9%, and carbon monoxide by 23.8%; (2) when working on MFE: carbon black by 6.4 times, nitrogen oxides by 29.6%, carbon dioxide by 10.1%, and carbon oxide by 47.6%; (3) when working on EFE: carbon black by 4.8 times; nitrogen oxides by 40.3%, carbon dioxide by 26.6%, and carbon monoxide by 28.6%. The prospects of use of environmentally friendly energy carriers in diesels of mobile HPPs, such as natural gas, ethanol, and methanol, has been determined.

  11. How High Local Charge Carrier Mobility and an Energy Cascade in a Three-Phase Bulk Heterojunction Enable >90% Quantum Efficiency

    KAUST Repository

    Burke, Timothy M.

    2013-12-27

    Charge generation in champion organic solar cells is highly efficient in spite of low bulk charge-carrier mobilities and short geminate-pair lifetimes. In this work, kinetic Monte Carlo simulations are used to understand efficient charge generation in terms of experimentally measured high local charge-carrier mobilities and energy cascades due to molecular mixing. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. How High Local Charge Carrier Mobility and an Energy Cascade in a Three-Phase Bulk Heterojunction Enable >90% Quantum Efficiency

    KAUST Repository

    Burke, Timothy M.; McGehee, Michael D.

    2013-01-01

    Charge generation in champion organic solar cells is highly efficient in spite of low bulk charge-carrier mobilities and short geminate-pair lifetimes. In this work, kinetic Monte Carlo simulations are used to understand efficient charge generation in terms of experimentally measured high local charge-carrier mobilities and energy cascades due to molecular mixing. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Determination of charge carrier mobility of hole transporting polytriarylamine-based diodes

    International Nuclear Information System (INIS)

    Barea, Eva M.; Garcia-Belmonte, Germa; Sommer, Michael; Huettner, Sven; Bolink, Henk J.; Thelakkat, Mukundan

    2010-01-01

    Hole transport properties of three different side chain poly(triarylamines) have been determined by means of the analysis of steady-state current-voltage characteristics using co-planar diode structures. The interpretation is based on space-charge limited models with field-dependent mobility. Mobilities between ∼ 10 -8 and 10 -6 cm 2 V -1 s -1 are obtained. The highest mobility is achieved for poly(tetraphenylbenzidine) devices and the lowest for poly(triphenylamine) devices. Electron-rich methoxy substituents increase the mobility of poly(triphenylamine)s. A comparison of the mobility values with those obtained using organic field-effect transistors is also given.

  14. Investigations of the drift mobility of carriers and density of states in nanocrystalline CdS thin films

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Baljinder [Department of Physics, Kurukshetra University, Kurukshetra 136119 (India); Department of Physics, Panjab University, Chandigarh 160014 (India); Singh, Janpreet; Kaur, Jagdish [Department of Physics, Panjab University, Chandigarh 160014 (India); Moudgil, R.K. [Department of Physics, Kurukshetra University, Kurukshetra 136119 (India); Tripathi, S.K., E-mail: surya@pu.ac.in [Department of Physics, Panjab University, Chandigarh 160014 (India)

    2016-06-01

    Nanocrystalline Cadmium Sulfide (nc-CdS) thin films have been prepared on well-cleaned glass substrate at room temperature (300 K) by thermal evaporation technique using inert gas condensation (IGC) method. X-ray diffraction (XRD) analysis reveals that the films crystallize in hexagonal structure with preferred orientation along [002] direction. Scanning electron microscope (SEM) and Transmission electron microscope (TEM) studies reveal that grains are spherical in shape and uniformly distributed over the glass substrates. The optical band gap of the film is estimated from the transmittance spectra. Electrical parameters such as Hall coefficient, carrier type, carrier concentration, resistivity and mobility are determined using Hall measurements at 300 K. Transit time and mobility are estimated from Time of Flight (TOF) transient photocurrent technique in gap cell configuration. The measured values of electron drift mobility from TOF and Hall measurements are of the same order. Constant Photocurrent Method in ac-mode (ac-CPM) is used to measure the absorption spectra in low absorption region. By applying derivative method, we have converted the measured absorption data into a density of states (DOS) distribution in the lower part of the energy gap. The value of Urbach energy, steepness parameter and density of defect states have been calculated from the absorption and DOS spectra.

  15. Charge carrier mobility in poly[methyl(phenyl)silylene] studied by time-resolved terahertz spectroscopy and molecular modeling

    Czech Academy of Sciences Publication Activity Database

    Němec, Hynek; Kratochvílová, Irena; Kužel, Petr; Šebera, Jakub; Kochalska, Anna; Nožár, Juraj; Nešpůrek, Stanislav

    2011-01-01

    Roč. 13, č. 7 (2011), s. 2850-2856 ISSN 1463-9076 R&D Projects: GA ČR(CZ) GP202/09/P099; GA ČR GA203/08/1594; GA AV ČR KAN401770651; GA MŠk LC512; GA ČR(CZ) GAP304/10/1951 Institutional research plan: CEZ:AV0Z10100520; CEZ:AV0Z40500505 Keywords : molecular electronics * THz spectroscopy * charge carrier mobility Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.573, year: 2011

  16. Tuning the Electronic Properties, Effective Mass and Carrier Mobility of MoS2 Monolayer by Strain Engineering: First-Principle Calculations

    Science.gov (United States)

    Phuc, Huynh V.; Hieu, Nguyen N.; Hoi, Bui D.; Hieu, Nguyen V.; Thu, Tran V.; Hung, Nguyen M.; Ilyasov, Victor V.; Poklonski, Nikolai A.; Nguyen, Chuong V.

    2018-01-01

    In this paper, we studied the electronic properties, effective masses, and carrier mobility of monolayer MoS_2 using density functional theory calculations. The carrier mobility was considered by means of ab initio calculations using the Boltzmann transport equation coupled with deformation potential theory. The effects of mechanical biaxial strain on the electronic properties, effective mass, and carrier mobility of monolayer MoS_2 were also investigated. It is demonstrated that the electronic properties, such as band structure and density of state, of monolayer MoS_2 are very sensitive to biaxial strain, leading to a direct-indirect transition in semiconductor monolayer MoS_2. Moreover, we found that the carrier mobility and effective mass can be enhanced significantly by biaxial strain and by lowering temperature. The electron mobility increases over 12 times with a biaxial strain of 10%, while the carrier mobility gradually decreases with increasing temperature. These results are very useful for the future nanotechnology, and they make monolayer MoS_2 a promising candidate for application in nanoelectronic and optoelectronic devices.

  17. Impact of Gate Dielectric in Carrier Mobility in Low Temperature Chalcogenide Thin Film Transistors for Flexible Electronics

    KAUST Repository

    Salas-Villasenor, A. L.; Mejia, I.; Hovarth, J.; Alshareef, Husam N.; Cha, D. K.; Ramirez-Bon, R.; Gnade, B. E.; Quevedo-Lopez, M. A.

    2010-01-01

    Cadmium sulfide thin film transistors were demonstrated as the n-type device for use in flexible electronics. CdS thin films were deposited by chemical bath deposition (70° C) on either 100 nm HfO2 or SiO2 as the gate dielectrics. Common gate transistors with channel lengths of 40-100 μm were fabricated with source and drain aluminum top contacts defined using a shadow mask process. No thermal annealing was performed throughout the device process. X-ray diffraction results clearly show the hexagonal crystalline phase of CdS. The electrical performance of HfO 2 /CdS -based thin film transistors shows a field effect mobility and threshold voltage of 25 cm2 V-1 s-1 and 2 V, respectively. Improvement in carrier mobility is associated with better nucleation and growth of CdS films deposited on HfO2. © 2010 The Electrochemical Society.

  18. Impact of Gate Dielectric in Carrier Mobility in Low Temperature Chalcogenide Thin Film Transistors for Flexible Electronics

    KAUST Repository

    Salas-Villasenor, A. L.

    2010-06-29

    Cadmium sulfide thin film transistors were demonstrated as the n-type device for use in flexible electronics. CdS thin films were deposited by chemical bath deposition (70° C) on either 100 nm HfO2 or SiO2 as the gate dielectrics. Common gate transistors with channel lengths of 40-100 μm were fabricated with source and drain aluminum top contacts defined using a shadow mask process. No thermal annealing was performed throughout the device process. X-ray diffraction results clearly show the hexagonal crystalline phase of CdS. The electrical performance of HfO 2 /CdS -based thin film transistors shows a field effect mobility and threshold voltage of 25 cm2 V-1 s-1 and 2 V, respectively. Improvement in carrier mobility is associated with better nucleation and growth of CdS films deposited on HfO2. © 2010 The Electrochemical Society.

  19. Determination of charge carrier mobility of hole transporting polytriarylamine-based diodes

    Energy Technology Data Exchange (ETDEWEB)

    Barea, Eva M. [Photovoltaic and Optoelectronic Devices Group, Departament de Fisica, Universitat Jaume I, 12071 Castello (Spain); Garcia-Belmonte, Germa, E-mail: garciag@uji.e [Photovoltaic and Optoelectronic Devices Group, Departament de Fisica, Universitat Jaume I, 12071 Castello (Spain); Sommer, Michael; Huettner, Sven [Applied Functional Polymers, Universitaet Bayreuth, 95440 Bayreuth (Germany); Bolink, Henk J. [Molecular Science Institute-Universitat de Valencia, Poligon La Coma s/n, 46980 Paterna, Valencia (Spain); Thelakkat, Mukundan, E-mail: mukundan.thelakkat@uni-bayreuth.d [Applied Functional Polymers, Universitaet Bayreuth, 95440 Bayreuth (Germany)

    2010-04-02

    Hole transport properties of three different side chain poly(triarylamines) have been determined by means of the analysis of steady-state current-voltage characteristics using co-planar diode structures. The interpretation is based on space-charge limited models with field-dependent mobility. Mobilities between {approx} 10{sup -8} and 10{sup -6} cm{sup 2} V{sup -1} s{sup -1} are obtained. The highest mobility is achieved for poly(tetraphenylbenzidine) devices and the lowest for poly(triphenylamine) devices. Electron-rich methoxy substituents increase the mobility of poly(triphenylamine)s. A comparison of the mobility values with those obtained using organic field-effect transistors is also given.

  20. Quantum calculations of the carrier mobility: Methodology, Matthiessen's rule, and comparison with semi-classical approaches

    Energy Technology Data Exchange (ETDEWEB)

    Niquet, Yann-Michel, E-mail: yniquet@cea.fr; Nguyen, Viet-Hung; Duchemin, Ivan [L-Sim, SP2M, UMR-E CEA/UJF-Grenoble 1, INAC, Grenoble (France); Triozon, François [CEA, LETI-MINATEC, Grenoble (France); Nier, Olivier; Rideau, Denis [ST Microelectronics, Crolles (France)

    2014-02-07

    We discuss carrier mobilities in the quantum Non-Equilibrium Green's Functions (NEGF) framework. We introduce a method for the extraction of the mobility that is free from contact resistance contamination and with minimal needs for ensemble averages. We focus on silicon thin films as an illustration, although the method can be applied to various materials such as semiconductor nanowires or carbon nanostructures. We then introduce a new paradigm for the definition of the partial mobility μ{sub M} associated with a given elastic scattering mechanism “M,” taking phonons (PH) as a reference (μ{sub M}{sup −1}=μ{sub PH+M}{sup −1}−μ{sub PH}{sup −1}). We argue that this definition makes better sense in a quantum transport framework as it is free from long range interference effects that can appear in purely ballistic calculations. As a matter of fact, these mobilities satisfy Matthiessen's rule for three mechanisms [e.g., surface roughness (SR), remote Coulomb scattering (RCS) and phonons] much better than the usual, single mechanism calculations. We also discuss the problems raised by the long range spatial correlations in the RCS disorder. Finally, we compare semi-classical Kubo-Greenwood (KG) and quantum NEGF calculations. We show that KG and NEGF are in reasonable agreement for phonon and RCS, yet not for SR. We discuss the reasons for these discrepancies.

  1. 300% Enhancement of Carrier Mobility in Uniaxial-Oriented Perovskite Films Formed by Topotactic-Oriented Attachment.

    Science.gov (United States)

    Kim, Dong Hoe; Park, Jaehong; Li, Zhen; Yang, Mengjin; Park, Ji-Sang; Park, Ik Jae; Kim, Jin Young; Berry, Joseph J; Rumbles, Garry; Zhu, Kai

    2017-06-01

    Organic-inorganic perovskites with intriguing optical and electrical properties have attracted significant research interests due to their excellent performance in optoelectronic devices. Recent efforts on preparing uniform and large-grain polycrystalline perovskite films have led to enhanced carrier lifetime up to several microseconds. However, the mobility and trap densities of polycrystalline perovskite films are still significantly behind their single-crystal counterparts. Here, a facile topotactic-oriented attachment (TOA) process to grow highly oriented perovskite films, featuring strong uniaxial-crystallographic texture, micrometer-grain morphology, high crystallinity, low trap density (≈4 × 10 14 cm -3 ), and unprecedented 9 GHz charge-carrier mobility (71 cm 2 V -1 s -1 ), is demonstrated. TOA-perovskite-based n-i-p planar solar cells show minimal discrepancies between stabilized efficiency (19.0%) and reverse-scan efficiency (19.7%). The TOA process is also applicable for growing other state-of-the-art perovskite alloys, including triple-cation and mixed-halide perovskites. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Determination of energy band diagram and charge carrier mobility of white emitting polymer from optical, electrical and impedance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Mohd Sarjidan, M.A., E-mail: mohd.arif@um.edu.my; Mohd Mokhtar, H.A.; Abd Majid, W.H., E-mail: q3haliza@um.edu.my

    2015-03-15

    A single-layer white polymer light-emitting device (WPLED) has been fabricated using spin coating technique. The device was constructed as ITO/PEDOT:PSS(50 nm)/SPW-111(50 nm)/LiF(1 nm)/Al(100 nm). Indium tin oxide (ITO) and poly(3,4-ethylenedioxythiophene) Polystyrene sulfonate (PEDOT:PSS) are used as the transparent anode. SPW-111 is fabricated as a white emissive layer and lithium fluoride (LiF) and aluminum (Al) are used as reflecting cathode. Energy band diagram of the device was estimated from a combination of ultraviolet–visible (UV–vis) and current–voltage (J–V) analyses. Charge carrier mobility (μ) of PLED was evaluated using negative differential susceptance (−ΔB) method from impedance spectroscopy (IS) analysis. The calculated μ of the SPW-111 device is in the magnitude of 10{sup −6} cm{sup 2}/V/s. - Highlights: • Single layer PLED has been fabricated with spin-coating technique and device performance has been evaluated. • Energy band diagram of the SPW-111 is estimated from optical and electrical analyses. • Charge carrier mobility of the SPW-111 materials is obtained by impedance spectroscopy.

  3. Achieving high carrier mobility exceeding 70 cm2/Vs in amorphous zinc tin oxide thin-film transistors

    Science.gov (United States)

    Kim, Sang Tae; Shin, Yeonwoo; Yun, Pil Sang; Bae, Jong Uk; Chung, In Jae; Jeong, Jae Kyeong

    2017-09-01

    This paper proposes a new defect engineering concept for low-cost In- and Ga-free zinc tin oxide (ZTO) thin-film transistors (TFTs). This concept is comprised of capping ZTO films with tantalum (Ta) and a subsequent modest thermal annealing treatment at 200 °C. The Ta-capped ZTO TFTs exhibited a remarkably high carrier mobility of 70.8 cm2/Vs, low subthreshold gate swing of 0.18 V/decade, threshold voltage of -1.3 V, and excellent ION/OFF ratio of 2 × 108. The improvement (> two-fold) in the carrier mobility compared to the uncapped ZTO TFT can be attributed to the effective reduction of the number of adverse tailing trap states, such as hydroxyl groups or oxygen interstitial defects, which stems from the scavenging effect of the Ta capping layer on the ZTO channel layer. Furthermore, the Ta-capped ZTO TFTs showed excellent positive and negative gate bias stress stabilities. [Figure not available: see fulltext.

  4. Thermal generation and mobility of charge carriers in collective proton transport in hydrogen-bonded chains

    International Nuclear Information System (INIS)

    Peyrard, M.; Boesch, R.; Kourakis, I.

    1991-01-01

    The transport of protons in hydrogen-bonded systems is a long standing problem which has not yet obtained a satisfactorily theoretical description. Although this problem was examined first for ice, it is relevant in many systems and in particular in biology for the transport along proteins or for proton conductance across membranes, an essential process in cell life. The broad relevance makes the study of proton conduction very appealing. Since the original work of Bernal and Fowler on ice, the idea that the transport occurs through chains of hydrogen bonds has been well accepted. Such ''proton wires'' were invoked by Nagle and Morowitz for proton transport across membranes proteins and more recently across lipid bilayers. In this report, we assume the existence of such an hydrogen-bonded chain and discuss its consequences on the dynamics of the charge carriers. We show that this assumption leads naturally to the idea of soliton transport and we put a special emphasis on the role of the coupling between the protons and heavy ions motions. The model is presented. We show how the coupling affects strongly the dynamics of the charge carriers and we discuss the role it plays in the thermal generation of carriers. The work presented has been performed in 1986 and 87 with St. Pnevmatikos and N. Flyzanis and was then completed in collaboration with D. Hochstrasser and H. Buettner. Therefore the results presented in this part are not new but we think that they are appropriate in the context of this multidisciplinary workshop because they provide a rather complete example of the soliton picture for proton conduction. This paper discusses the thermal generation of the charge carriers when the coupling between the protons and heavy ions dynamics is taken into account. The results presented in this part are very recent and will deserve further analysis but they already show that the coupling can assist for the formation of the charge carriers

  5. Frequency and temperature dependent mobility of a charged carrier and randomly interrupted strand

    International Nuclear Information System (INIS)

    Kumar, N.; Jayannavar, A.M.

    1981-05-01

    Randomly interrupted strand model of a one-dimensional conductor is considered. Exact analytical expression is obtained for the temperature dependent as mobility for a finite segment drawn at random, taking into account the reflecting barriers at the two open ends. The real part of mobility shows a broad resonance as a function of both frequency and tempeature, and vanishes quadratically in the dc limit. The frequency (temperature) maximum shifts to higher values for higher temperatures (frequencies). (author)

  6. Driving Sustainable Competitive Advantage in the Mobile Industry: Evidence from U.S. Wireless Carriers

    Directory of Open Access Journals (Sweden)

    Changhee Kim

    2016-07-01

    Full Text Available In light of the growing importance of data network quality in the wireless industry, this study analyzes and compares efficiencies in management, service quality, network quality, and market in the 4G Long Term Evolution (LTE wireless industry. For this purpose, a bootstrap data envelopment analysis (DEA model using representative U.S. wireless carriers as decision making units (DMUs was designed and conducted, with further verification through the Mann-Whitney U and Wilcoxon W test, to examine the differences in efficiency distribution. The results indicate that, in terms of efficiency distribution, network quality efficiency and market efficiency belongs to the same group as that which has high management efficiency. Based on these results, this paper suggests implications and strategic guidelines for wireless carriers for improvement in management efficiency.

  7. Band gap tunning in BN-doped graphene systems with high carrier mobility

    KAUST Repository

    Kaloni, T. P.

    2014-02-17

    Using density functional theory, we present a comparative study of the electronic properties of BN-doped graphene monolayer, bilayer, trilayer, and multilayer systems. In addition, we address a superlattice of pristine and BN-doped graphene. Five doping levels between 12.5% and 75% are considered, for which we obtain band gaps from 0.02 eV to 2.43 eV. We demonstrate a low effective mass of the charge carriers.

  8. Toward High Carrier Mobility and Low Contact Resistance:Laser Cleaning of PMMA Residues on Graphene Surfaces

    Institute of Scientific and Technical Information of China (English)

    Yuehui Jia; Xin Gong; Pei Peng; Zidong Wang; Zhongzheng Tian; Liming Ren; Yunyi Fu; Han Zhang

    2016-01-01

    Poly(methyl methacrylate)(PMMA) is widely used for graphene transfer and device fabrication.However,it inevitably leaves a thin layer of polymer residues after acetone rinsing and leads to dramatic degradation of device performance.How to eliminate contamination and restore clean surfaces of graphene is still highly demanded.In this paper,we present a reliable and position-controllable method to remove the polymer residues on graphene films by laser exposure.Under proper laser conditions,PMMA residues can be substantially reduced without introducing defects to the underlying graphene.Furthermore,by applying this laser cleaning technique to the channel and contacts of graphene fieldeffect transistors(GFETs),higher carrier mobility as well as lower contact resistance can be realized.This work opens a way for probing intrinsic properties of contaminant-free graphene and fabricating high-performance GFETs with both clean channel and intimate graphene/metal contact.

  9. Improvement in carrier mobility and photovoltaic performance through random distribution of segments of linear and branched side chains

    Energy Technology Data Exchange (ETDEWEB)

    Egbe, Daniel A.M.; Adam, Getachew; Pivrikas, Almantas; Ulbricht, Christoph; Ramil, Alberto M.; Sariciftci, Niyazi Serdar [Johannes Kepler Univ., Linz (AT). Linz Inst. for Organic Solar Cells (LIOS); Hoppe, Harald [Technische Univ. Ilmenau (Germany). Inst. of Physics and Inst. of Micro- and Nanotechnologies; Rathgeber, Silke [Mainz Univ. (Germany). Inst. of Physics

    2010-07-01

    The random distribution of segments of linear octyloxy side chains and of branched 2-ethylhexyloxy side chains, on the backbone of anthracene containing poly(p-phenylene-ethynylene)-alt-poly(p-phenylene-vinylene) (PPE-PPV) has resulted in a side chain based statistical copolymer, denoted AnE-PVstat, showing optimized features as compared to the well defined homologues AnE-PVaa, -ab, -ba and -bb, whose constitutional units are incorporated into its backbone. WAXS studies on AnE-P's demonstrate the highest degree of order at the self-assembly state of AnE-PVstat, which is confirmed by its highly structured thin film absorption band. Electric field independent charge carrier mobility ({mu}{sub hole}) for AnE-PVstat was demonstrated by CELIV and OFET measurements, both methods resulting in similar {mu}{sub hole} values of up to 5.43 x 10{sup -4} cm{sup 2}/Vs. Upon comparison, our results show that charge carrier mobility as measured by CELIV technique is predominantly an intrachain process and less an interchain one, which is in line with past photoconductivity results from PPE-PPV based materials. The present side chain distribution favors efficient solar cell active layer phase separation. As a result, a smaller amount of PC{sub 60}BM is needed to achieve relatively high energy conversion efficiencies above 3 %. The efficiency of {eta}{sub AM1.5} {approx} 3.8 % obtained for AnE-PVstat:PC{sub 60}BM blend is presently the state-of-art value for PPV-based materials. (orig.)

  10. Ultra-high carrier mobility InSb film by rapid thermal annealing on glass substrate

    Directory of Open Access Journals (Sweden)

    Charith Jayanada Koswaththage

    2016-11-01

    Full Text Available InSb films were deposited on both mica and glass substrates using thermal evaporation and subjected to FA or RTA. Crystallinity, composition and electrical properties were investigated. High Hall electron mobility as high as 25,000 cm2/(Vs was obtained with the capped InSb film by keeping the In:Sb ratio after RTA at 520°C for 30 sec or more without adopting epitaxial growth on glass.

  11. High-resolution charge carrier mobility mapping of heterogeneous organic semiconductors

    Science.gov (United States)

    Button, Steven W.; Mativetsky, Jeffrey M.

    2017-08-01

    Organic electronic device performance is contingent on charge transport across a heterogeneous landscape of structural features. Methods are therefore needed to unravel the effects of local structure on overall electrical performance. Using conductive atomic force microscopy, we construct high-resolution out-of-plane hole mobility maps from arrays of 5000 to 16 000 current-voltage curves. To demonstrate the efficacy of this non-invasive approach for quantifying and mapping local differences in electrical performance due to structural heterogeneities, we investigate two thin film test systems, one bearing a heterogeneous crystal structure [solvent vapor annealed 5,11-Bis(triethylsilylethynyl)anthradithiophene (TES-ADT)—a small molecule organic semiconductor] and one bearing a heterogeneous chemical composition [p-DTS(FBTTh2)2:PC71BM—a high-performance organic photovoltaic active layer]. TES-ADT shows nearly an order of magnitude difference in hole mobility between semicrystalline and crystalline areas, along with a distinct boundary between the two regions, while p-DTS(FBTTh2)2:PC71BM exhibits subtle local variations in hole mobility and a nanoscale domain structure with features below 10 nm in size. We also demonstrate mapping of the built-in potential, which plays a significant role in organic light emitting diode and organic solar cell operation.

  12. Cooperative Transmission in Mobile Wireless Sensor Networks with Multiple Carrier Frequency Offsets: A Double-Differential Approach

    Directory of Open Access Journals (Sweden)

    Kun Zhao

    2014-01-01

    Full Text Available As a result of the rapidly increasing mobility of sensor nodes, mobile wireless sensor networks (MWSNs would be subject to multiple carrier frequency offsets (MCFOs, which result in time-varying channels and drastically degrade the network performance. To enhance the performance of such MWSNs, we propose a relay selection (RS based double-differential (DD cooperative transmission scheme, termed RSDDCT, in which the best relay sensor node is selected to forward the source sensor node’s signals to the destination sensor node with the detect-and-forward (DetF protocol. Assuming a Rayleigh fading environment, first, exact closed-form expressions for the outage probability and average bit error rate (BER of the RSDDCT scheme are derived. Then, simple and informative asymptotic outage probability and average BER expressions at the large signal-to-noise ratio (SNR regime are presented, which reveal that the RSDDCT scheme can achieve full diversity. Furthermore, the optimum power allocation strategy in terms of minimizing the average BER is investigated, and simple analytical solutions are obtained. Simulation results demonstrate that the proposed RSDDCT scheme can achieve excellent performance over fading channels in the presence of unknown random MCFOs. It is also shown that the proposed optimum power allocation strategy offers substantial average BER performance improvement over the equal power allocation strategy.

  13. Influence of the number of layers on ultrathin CsSnI3 perovskite: from electronic structure to carrier mobility

    Science.gov (United States)

    Liu, Biao; Long, Mengqiu; Cai, Meng-Qiu; Yang, Junliang

    2018-03-01

    Inorganic halide perovskites have attracted great attention in recent years as promising materials for optoelectronic devices, with ultrathin inorganic halide perovskites showing excellent properties and great potential applications. Herein, the intrinsic electronic and optical properties of ultrathin cesium tin tri-iodide (CsSnI3) perovskite with a varying number of layers are explored using first-principles calculations. The results reveal that ultrathin CsSnI3 is a direct band gap semiconductor, and the band gap continues to increase to 1.83 eV from 1.28 eV as the number of layers is reduced to one layer from the bulk. By decreasing the number of layers, the effective mass of ultrathin CsSnI3 increases, and the optical absorption intensity along the x and y directions shows that the linear dichroism becomes stronger and stronger. Furthermore, the carrier mobilities (µ) can be predicted, and they show obvious in-plane anisotropy. The µ of the electrons is higher than that of the holes, and the electron mobility along the y direction is higher than that along the x direction. The layer thickness does not distinctly influence the µ. The difference in the atomic orbital distribution has the nature of obvious anisotropy in ultrathin CsSnI3. This work suggests that ultrathin inorganic perovskite could be a potential candidate for future nano-optoelectronic devices.

  14. Ultrahigh Carrier Mobility Achieved in Photoresponsive Hybrid Perovskite Films via Coupling with Single-Walled Carbon Nanotubes

    KAUST Repository

    Li, Feng; Wang, Hong; Kufer, Dominik; Liang, Liangliang; Yu, Weili; Alarousu, Erkki; Ma, Chun; Li, Yangyang; Liu, Zhixiong; Liu, Changxu; Wei, Nini; Wang, Fei; Chen, Lang; Mohammed, Omar F.; Fratalocchi, Andrea; Liu, Xiaogang; Konstantatos, Gerasimos; Wu, Tao

    2017-01-01

    Organolead trihalide perovskites have drawn substantial interest for photovoltaic and optoelectronic applications due to their remarkable physical properties and low processing cost. However, perovskite thin films suffer from low carrier mobility as a result of their structural imperfections such as grain boundaries and pinholes, limiting their device performance and application potential. Here we demonstrate a simple and straightforward synthetic strategy based on coupling perovskite films with embedded single-walled carbon nanotubes. We are able to significantly enhance the hole and electron mobilities of the perovskite film to record-high values of 595.3 and 108.7 cm(2) V(-1) s(-1) , respectively. Such a synergistic effect can be harnessed to construct ambipolar phototransistors with an ultrahigh detectivity of 3.7 × 10(14) Jones and a responsivity of 1 × 10(4) A W(-1) , on a par with the best devices available to date. The perovskite/carbon nanotube hybrids should provide a platform that is highly desirable for fields as diverse as optoelectronics, solar energy conversion, and molecular sensing.

  15. Ultrahigh Carrier Mobility Achieved in Photoresponsive Hybrid Perovskite Films via Coupling with Single-Walled Carbon Nanotubes

    KAUST Repository

    Li, Feng

    2017-02-22

    Organolead trihalide perovskites have drawn substantial interest for photovoltaic and optoelectronic applications due to their remarkable physical properties and low processing cost. However, perovskite thin films suffer from low carrier mobility as a result of their structural imperfections such as grain boundaries and pinholes, limiting their device performance and application potential. Here we demonstrate a simple and straightforward synthetic strategy based on coupling perovskite films with embedded single-walled carbon nanotubes. We are able to significantly enhance the hole and electron mobilities of the perovskite film to record-high values of 595.3 and 108.7 cm(2) V(-1) s(-1) , respectively. Such a synergistic effect can be harnessed to construct ambipolar phototransistors with an ultrahigh detectivity of 3.7 × 10(14) Jones and a responsivity of 1 × 10(4) A W(-1) , on a par with the best devices available to date. The perovskite/carbon nanotube hybrids should provide a platform that is highly desirable for fields as diverse as optoelectronics, solar energy conversion, and molecular sensing.

  16. Insights into the charge carrier terahertz mobility in polyfluorenes from large-scale atomistic simulations and time-resolved terahertz spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Vukmirović, N.; Ponseca, C.S.; Němec, Hynek; Yartsev, A.; Sundström, V.

    2012-01-01

    Roč. 116, č. 37 (2012), s. 19665-1972 ISSN 1932-7447 Institutional research plan: CEZ:AV0Z10100520 Keywords : charge carrier mobility * time-resolved terahertz spectroscopy * multiscale atomistic calculations Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.814, year: 2012

  17. On the high charge-carrier mobility in polyaniline molecular channels in nanogaps between carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Emelianov, A. V., E-mail: emmsowton@gmail.com; Romashkin, A. V.; Tsarik, K. A. [National Research University of Electronic Technology (MIET) (Russian Federation); Nasibulin, A. G. [Skolkovo Institute of Science and Technology (Russian Federation); Nevolin, V. K.; Bobrinetskiy, I. I. [National Research University of Electronic Technology (MIET) (Russian Federation)

    2017-04-15

    This study is devoted to the fabrication of molecular semiconductor channels based on polymer molecules with nanoscale electrodes made of single-walled carbon nanotubes. A reproducible technology for forming nanoscale gaps in carbon nanotubes using a focused Ga{sup +} ion beam is proposed. Polyaniline molecules are deposited into nanogaps up to 30 nm wide between nanotubes by electrophoresis from N-methyl-2-pyrrolidone solution. As a result, molecular organic transistors are fabricated, in which the field effect is studied and the molecular-channel mobility is determined as 0.1 cm{sup 2}/(V s) at an on/off current ratio of 5 × 10{sup 2}.

  18. Field-effect measurements of mobility and carrier concentration of Cu2S colloidal quantum dot thin films after ligand exchange

    International Nuclear Information System (INIS)

    Brewer, Adam S.; Arnold, Michael S.

    2014-01-01

    Colloidal quantum dots (CQDs) of copper sulfide (Cu 2 S), an earth-abundant semiconductor, have a number of intriguing applications that require knowledge of their electrical properties. Depending on stoichiometry, mobility, and surface treatment, applications include photoabsorbers for solar cells, tunable plasmonics, and counter-electrodes for polysulfate electrolytes. However, there have not been any direct measurements of electrical properties in Cu 2 S CQD thin films. Here, we exchange as synthesized dodecanethiol ligands with short ethanedithiol or ethylenediamine ligands to form thin films of coupled Cu 2 S CQDs. The mobility and carrier concentration were found to vary by ligand treatment from 10 −5 cm 2 /Vs and 10 19 holes/cm 3 for ethanedithiol ligands to 10 −3 cm 2 /Vs and 10 20 holes/cm 3 for ethylenediamine. These results are consistent with the carrier concentrations inferred from sub-bandgap surface-plasmon-resonances measured by infrared spectroscopy. These results will be useful when designing Cu 2 S materials for future applications. - Highlights: • Colloidal Cu2S quantum dots were synthesized and characterized. • Ligand exchange was performed to alter the Cu2S nanocrystal properties. • Ligand exchange was studied using photoluminescence and infrared spectroscopy. • Field effect mobility and carrier concentration were directly measured. • Carrier concentration was compared to estimates from surface plasmon resonances

  19. Simultaneous enhancement of carrier mobility and concentration via tailoring of Al-chemical states in Al-ZnO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Manish, E-mail: manishk@skku.edu; Wen, Long; Sahu, Bibhuti B. [Center for Advance Plasma Surface Technology (CAPST), NU-SKKU Joint Institute for Plasma-Nano Materials (IPNM), School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon-440746 (Korea, Republic of); Han, Jeon Geon [Center for Advance Plasma Surface Technology (CAPST), NU-SKKU Joint Institute for Plasma-Nano Materials (IPNM), School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon-440746 (Korea, Republic of); Department of Industrial Engineering, Faculty of Engineering, Chiang Mai University, Chiang Mai-50200 (Thailand)

    2015-06-15

    Simultaneously achieving higher carriers concentration and mobility is a technical challenge against up-scaling the transparent-conductive performances of transparent-conductive oxides. Utilizing one order higher dense (∼1 × 10{sup 11} cm{sup −3}) plasmas (in comparison to the conventional direct current plasmas), highly c-axis oriented Al-doped ZnO films have been prepared with precise control over relative composition and chemical states of constituting elements. Tailoring of intrinsic (O vacancies) and extrinsic (ionic Al and zero-valent Al) dopants provide simultaneous enhancement in mobility and concentration of charge carriers. Room-temperature resistivity as low as 4.89 × 10{sup −4} Ω cm along the carrier concentration 5.6 × 10{sup 20} cm{sup −3} is obtained in 200 nm thick transparent films. Here, the control of atomic Al reduces the charge trapping at grain boundaries and subdues the effects of grain boundary scattering. A mechanism based on the correlation between electron-hole interaction and carrier mobility is proposed for degenerately doped wide band-gap semiconductors.

  20. High-temperature carrier density and mobility enhancements in AlGaN/GaN HEMT using AlN spacer layer

    Science.gov (United States)

    Ko, Tsung-Shine; Lin, Der-Yuh; Lin, Chia-Feng; Chang, Che-Wei; Zhang, Jin-Cheng; Tu, Shang-Ju

    2017-04-01

    In this paper, we experimentally studied the effect of AlN spacer layer on optical and electrical properties of AlGaN/GaN high electric mobility transistors (HEMTs) grown by metal organic chemical vapor deposition method. For AlGaN layer in HEMT structure, the Al composition of the sample was determined using x-ray diffraction and photoluminescence. Electrolyte electro-reflectance (EER) measurement not only confirmed the aluminum composition of AlGaN layer, but also determined the electric field strength on the AlGaN layer through the Franz-Keldysh oscillation phenomenon. This result indicated that the electric field on the AlGaN layer could be improved from 430 to 621 kV/cm when AlN spacer layer was inserted in HEMT structure, which increased the concentration of two dimensional electron gas (2DEG) and improve the mobility. The temperature dependent Hall results show that both the mobility and the carrier concentration of 2DEG would decrease abruptly causing HEMT loss of function due to phonon scattering and carrier thermal escape when temperature increases above a specific value. Meanwhile, our study also demonstrates using AlN spacer layer could be beneficial to allow the mobility and carrier density of 2DEG sustaining at high temperature region.

  1. Organic-inorganic hybrid perovskite quantum dots with high PLQY and enhanced carrier mobility through crystallinity control by solvent engineering and solid-state ligand exchange.

    Science.gov (United States)

    Woo Choi, Jin; Woo, Hee Chul; Huang, Xiaoguang; Jung, Wan-Gil; Kim, Bong-Joong; Jeon, Sie-Wook; Yim, Sang-Youp; Lee, Jae-Suk; Lee, Chang-Lyoul

    2018-05-22

    The photoluminescence quantum yield (PLQY) and charge carrier mobility of organic-inorganic perovskite QDs were enhanced by the optimization of crystallinity and surface passivation as well as solid-state ligand exchange. The crystallinity of perovskite QDs was determined by the Effective solvent field (Esol) of various solvents for precipitation. The solvent with high Esol could more quickly countervail the localized field generated by the polar solvent, and it causes fast crystallization of the dissolved precursor, which results in poor crystallinity. The post-ligand adding process (PLAP) and post-ligand exchange process (PLEP) increase the PLQY of perovskite QDs by reducing non-radiative recombination and the density of surface defect states through surface passivation. Particularly, the post ligand exchange process (PLEP) in the solid-state improved the charge carrier mobility of perovskite QDs in addition to the PLQY enhancement. The ligand exchange with short alkyl chain length ligands could improve the packing density of perovskite QDs in films by reducing the inter-particle distance between perovskite QDs. The maximum hole mobility of 6.2 × 10-3 cm2 V-1 s-1, one order higher than that of pristine QDs without the PLEP, is obtained at perovskite QDs with hexyl ligands. By using PLEP treatment, compared to the pristine device, a 2.5 times higher current efficiency in perovskite QD-LEDs was achieved due to the improved charge carrier mobility and PLQY.

  2. Thickness and growth-condition dependence of in-situ mobility and carrier density of epitaxial thin-film Bi2Se3

    International Nuclear Information System (INIS)

    Hellerstedt, Jack; Fuhrer, Michael S.; Edmonds, Mark T.; Zheng, C. X.; Chen, J. H.; Cullen, William G.

    2014-01-01

    Bismuth selenide Bi 2 Se 3 was grown by molecular beam epitaxy, while carrier density and mobility were measured directly in situ as a function of film thickness. Carrier density shows high interface n-doping (1.5 × 10 13  cm −2 ) at the onset of film conduction and bulk dopant density of ∼5 × 10 11  cm −2 per quintuple-layer unit, roughly independent of growth temperature profile. Mobility depends more strongly on the growth temperature and is related to the crystalline quality of the samples quantified by ex-situ atomic force microscopy measurements. These results indicate that Bi 2 Se 3 as prepared by widely employed parameters is n-doped before exposure to atmosphere, the doping is largely interfacial in origin, and dopants are not the limiting disorder in present Bi 2 Se 3 films.

  3. Exploring the validity and limitations of the Mott-Gurney law for charge-carrier mobility determination of semiconducting thin-films

    Science.gov (United States)

    Röhr, Jason A.; Moia, Davide; Haque, Saif A.; Kirchartz, Thomas; Nelson, Jenny

    2018-03-01

    Using drift-diffusion simulations, we investigate the voltage dependence of the dark current in single carrier devices typically used to determine charge-carrier mobilities. For both low and high voltages, the current increases linearly with the applied voltage. Whereas the linear current at low voltages is mainly due to space charge in the middle of the device, the linear current at high voltage is caused by charge-carrier saturation due to a high degree of injection. As a consequence, the current density at these voltages does not follow the classical square law derived by Mott and Gurney, and we show that for trap-free devices, only for intermediate voltages, a space-charge-limited drift current can be observed with a slope that approaches a value of two. We show that, depending on the thickness of the semiconductor layer and the size of the injection barriers, the two linear current-voltage regimes can dominate the whole voltage range, and the intermediate Mott-Gurney regime can shrink or disappear. In this case, which will especially occur for thicknesses and injection barriers typical of single-carrier devices used to probe organic semiconductors, a meaningful analysis using the Mott-Gurney law will become unachievable, because a square-law fit can no longer be achieved, resulting in the mobility being substantially underestimated. General criteria for when to expect deviations from the Mott-Gurney law when used for analysis of intrinsic semiconductors are discussed.

  4. Exploring the validity and limitations of the Mott-Gurney law for charge-carrier mobility determination of semiconducting thin-films.

    Science.gov (United States)

    Röhr, Jason A; Moia, Davide; Haque, Saif A; Kirchartz, Thomas; Nelson, Jenny

    2018-03-14

    Using drift-diffusion simulations, we investigate the voltage dependence of the dark current in single carrier devices typically used to determine charge-carrier mobilities. For both low and high voltages, the current increases linearly with the applied voltage. Whereas the linear current at low voltages is mainly due to space charge in the middle of the device, the linear current at high voltage is caused by charge-carrier saturation due to a high degree of injection. As a consequence, the current density at these voltages does not follow the classical square law derived by Mott and Gurney, and we show that for trap-free devices, only for intermediate voltages, a space-charge-limited drift current can be observed with a slope that approaches a value of two. We show that, depending on the thickness of the semiconductor layer and the size of the injection barriers, the two linear current-voltage regimes can dominate the whole voltage range, and the intermediate Mott-Gurney regime can shrink or disappear. In this case, which will especially occur for thicknesses and injection barriers typical of single-carrier devices used to probe organic semiconductors, a meaningful analysis using the Mott-Gurney law will become unachievable, because a square-law fit can no longer be achieved, resulting in the mobility being substantially underestimated. General criteria for when to expect deviations from the Mott-Gurney law when used for analysis of intrinsic semiconductors are discussed.

  5. Stability and carrier mobility of organic-inorganic hybrid perovskite CH3NH3PbI3 in two-dimensional limit

    Science.gov (United States)

    Huang, Kui; Lai, Kang; Yan, Chang-Lin; Zhang, Wei-Bing

    2017-10-01

    Recently, atomically thin organic-inorganic hybrid perovskites have been synthesized experimentally, which opens up new opportunities for exploring their novel properties in the 2D limit. Based on the comparative density functional theory calculation with and without spin-orbit coupling effects, the stability, electronic structure, and carrier mobility of the two-dimensional organic-inorganic hybrid perovskites MAPbI3 (MA = CH3NH3) have been investigated systemically. Two single-unit-cell-thick 2D MAPbI3 terminated by PbI2 and CH3NH3I are constructed, and their thermodynamic stabilities are also evaluated using the first-principles constrained thermodynamics method. Our results indicate that both 2D MAPbI3 with different terminations can be stable under certain conditions and have a suitable direct bandgap. Moreover, they are also found to have termination-dependent band edge and carrier mobility. The acoustic-phonon-limited carrier mobilities estimated using the deformation theory and effective mass approximation are on the order of thousands of square centimeters per volt per second and also highly anisotropic. These results indicate that 2D MAPbI3 are competitive candidates for low-dimensional photovoltaic applications.

  6. Interplay between hopping and band transport in high-mobility disordered semiconductors at large carrier concentrations: The case of the amorphous oxide InGaZnO

    Science.gov (United States)

    Fishchuk, I. I.; Kadashchuk, A.; Bhoolokam, A.; de Jamblinne de Meux, A.; Pourtois, G.; Gavrilyuk, M. M.; Köhler, A.; Bässler, H.; Heremans, P.; Genoe, J.

    2016-05-01

    We suggest an analytic theory based on the effective medium approximation (EMA) which is able to describe charge-carrier transport in a disordered semiconductor with a significant degree of degeneration realized at high carrier concentrations, especially relevant in some thin-film transistors (TFTs), when the Fermi level is very close to the conduction-band edge. The EMA model is based on special averaging of the Fermi-Dirac carrier distributions using a suitably normalized cumulative density-of-state distribution that includes both delocalized states and the localized states. The principal advantage of the present model is its ability to describe universally effective drift and Hall mobility in heterogeneous materials as a function of disorder, temperature, and carrier concentration within the same theoretical formalism. It also bridges a gap between hopping and bandlike transport in an energetically heterogeneous system. The key assumption of the model is that the charge carriers move through delocalized states and that, in addition to the tail of the localized states, the disorder can give rise to spatial energy variation of the transport-band edge being described by a Gaussian distribution. It can explain a puzzling observation of activated and carrier-concentration-dependent Hall mobility in a disordered system featuring an ideal Hall effect. The present model has been successfully applied to describe experimental results on the charge transport measured in an amorphous oxide semiconductor, In-Ga-Zn-O (a-IGZO). In particular, the model reproduces well both the conventional Meyer-Neldel (MN) compensation behavior for the charge-carrier mobility and inverse-MN effect for the conductivity observed in the same a-IGZO TFT. The model was further supported by ab initio calculations revealing that the amorphization of IGZO gives rise to variation of the conduction-band edge rather than to the creation of localized states. The obtained changes agree with the one we

  7. Suppressed carrier density for the patterned high mobility two-dimensional electron gas at γ-Al2O3/SrTiO3 heterointerfaces

    DEFF Research Database (Denmark)

    Niu, Wei; Gan, Yulin; Christensen, Dennis Valbjørn

    2017-01-01

    The two-dimensional electron gas (2DEG) at the non-isostructural interface between spinel γ-Al2O3 and perovskite SrTiO3 is featured by a record electron mobility among complex oxide interfaces in addition to a high carrier density up to the order of 1015 cm-2. Herein, we report on the patterning...... is found to be approximately 3×1013 cm-2, much lower than that of the unpatterned sample (~1015 cm-2). Remarkably, a high electron mobility of approximately 3,600 cm2V-1s-1 was obtained at low temperatures for the patterned 2DEG at a carrier density of ~ 7×1012 cm-2, which exhibits clear Shubnikov-de Hass...... quantum oscillations. The patterned high-mobility 2DEG at the γ-Al2O3/SrTiO3 interface paves the way for the design and application of spinel/perovskite interfaces for high-mobility all-oxide electronic devic...

  8. Analysis of defect structure in silicon. Effect of grain boundary density on carrier mobility in UCP material

    Science.gov (United States)

    Dunn, J.; Stringfellow, G. B.; Natesh, R.

    1982-01-01

    The relationships between hole mobility and grain boundary density were studied. Mobility was measured using the van der Pauw technique, and grain boundary density was measured using a quantitative microscopy technique. Mobility was found to decrease with increasing grain boundary density.

  9. Monolayer CS as a metal-free photocatalyst with high carrier mobility and tunable band structure: a first-principles study

    Science.gov (United States)

    Yang, Xiao-Le; Ye, Xiao-Juan; Liu, Chun-Sheng; Yan, Xiao-Hong

    2018-02-01

    Producing hydrogen fuel using suitable photocatalysts from water splitting is a feasible method to harvest solar energy. A desired photocatalyst is expected to have suitable band gap, moderate band edge position, and high carrier mobility. By employing first-principles calculations, we explore a α-CS monolayer as a metal-free efficient photocatalyst. The α-CS monolayer shows good energetic, dynamic, and thermal stabilities and is insoluble in water, suggesting its experimental practicability. Monolayer and bilayer α-CS present not only appropriate band gaps for visible and ultraviolet light absorption but also moderate band alignments with water redox potentials in pH neutral water. Remarkably, the α-CS monolayer exhibits high (up to 8453.19 cm2 V-1s-1 for hole) and anisotropic carrier mobility, which is favorable to the migration and separation of photogenerated carriers. In addition, monolayer α-CS experiences an interesting semiconductor-metal transition by applying uniaxial strain and external electric field. Moreover, α-CS under certain strain and electric field is still dynamically stable with the absence of imaginary frequencies. Furthermore, we demonstrate that the graphite (0 0 1) surface is a potential substrate for the α-CS growth with the intrinsic properties of α-CS maintaining. Therefore, our results could pave the way for the application of α-CS as a promising photocatalyst.

  10. Equivalence of donor and acceptor fits of temperature dependent Hall carrier density and Hall mobility data: Case of ZnO

    International Nuclear Information System (INIS)

    Brochen, Stéphane; Feuillet, Guy; Pernot, Julien

    2014-01-01

    In this work, statistical formulations of the temperature dependence of ionized and neutral impurity concentrations in a semiconductor, needed in the charge balance equation and for carrier scattering calculations, have been developed. These formulations have been used in order to elucidate a confusing situation, appearing when compensating acceptor (donor) levels are located sufficiently close to the conduction (valence) band to be thermally ionized and thereby to emit (capture) an electron to (from) the conduction (valence) band. In this work, the temperature dependent Hall carrier density and Hall mobility data adjustments are performed in an attempt to distinguish the presence of a deep acceptor or a deep donor level, coexisting with a shallower donor level and located near the conduction band. Unfortunately, the present statistical developments, applied to an n-type hydrothermal ZnO sample, lead in both cases to consistent descriptions of experimental Hall carrier density and mobility data and thus do not allow to determine the nature, donor or acceptor, of the deep level. This demonstration shows that the emission of an electron in the conduction band, generally assigned to a (0/+1) donor transition from a donor level cannot be applied systematically and could also be attributed to a (−1/0) donor transition from an acceptor level. More generally, this result can be extended for any semiconductor and also for deep donor levels located close to the valence band (acceptor transition)

  11. Anisotropic mobility and carrier dynamics in the β-type BEDT-TTF salts as studied by inter-layer transverse magnetoresistance

    Directory of Open Access Journals (Sweden)

    Shigeharu Sugawara and Masafumi Tamura

    2013-01-01

    Full Text Available A new method to estimate an in-plane conduction anisotropy in a quasi-two-dimensional (q2D layered conductor by measuring the inter-layer transverse magnetoresistance is proposed. We applied this method to layered organic conductors β-(BEDT-TTF2X (BEDT-TTF = bis(ethylenedithiotetrathiafulvalene, C10H8S8; X = IBr2, I2Br by applying magnetic field rotating within the basal plane at 4.2 K. We found the anisotropic behaviour of carrier mobility μ. From this, anomalous distribution of carrier lifetime τ on the Fermi surface is derived, by the use of Fermi surface data reported for the materials. Calculations of the non-uniform susceptibility χ0(q suggest that carrier scattering is enhanced at specific k-points related to partial nesting of the Fermi surface. The present method is thus demonstrated to be an efficient experimental tool to elucidate anisotropic carrier dynamics in q2D conductors.

  12. Mobility of charge carriers in electron-irradiated crystals of n-type Hg0.8Cd0.2Te

    International Nuclear Information System (INIS)

    Voitsekhovskii, A.V.; Kiryushkin, E.M.; Kokhanenko, A.P.; Kurbanov, K.R.; Lilenko, Yu.V.

    1988-01-01

    We present the results of an investigation of the behavior of the mobility of the charge carriers in Hg 1-x Cd x Te crystals with n-type conduction as a function of the dose of irradiation by electrons with an energy of 3.0 MeV at 300 K and the initial content of defects in the material. The complex character of the variation of the mobility of the electrons as a function of the dose observed when crystals of n-Hg 1-x Cd x Te (x ∼ 0.20) with different initial concentrations of defects are irradiated by fast electrons has been attributed to the influence of the factors of the shielding of the ionized scattering centers by electrons and the additional scattering of the charge carriers on the radiation defects. Good agreement between the experimental and calculated plots of the dependence of the mobility of electrons on the irradiation dose has been obtained with consideration of a model of the simultaneous introduction of donor (single charged) and acceptor (doubly charged) defects into a narrow-band semiconductor characterized by a degenerate and nonparabolic conduction band

  13. Unraveling Unprecedented Charge Carrier Mobility through Structure Property Relationship of Four Isomers of Didodecyl[1]benzothieno[3,2-b][1]benzothiophene.

    Science.gov (United States)

    Tsutsui, Yusuke; Schweicher, Guillaume; Chattopadhyay, Basab; Sakurai, Tsuneaki; Arlin, Jean-Baptiste; Ruzié, Christian; Aliev, Almaz; Ciesielski, Artur; Colella, Silvia; Kennedy, Alan R; Lemaur, Vincent; Olivier, Yoann; Hadji, Rachid; Sanguinet, Lionel; Castet, Frédéric; Osella, Silvio; Dudenko, Dmytro; Beljonne, David; Cornil, Jérôme; Samorì, Paolo; Seki, Shu; Geerts, Yves H

    2016-09-01

    The structural and electronic properties of four isomers of didodecyl[1]-benzothieno[3,2-b][1]benzothiophene (C12-BTBT) have been investigated. Results show the strong impact of the molecular packing on charge carrier transport and electronic polarization properties. Field-induced time-resolved microwave conductivity measurements unravel an unprecedented high average interfacial mobility of 170 cm(2) V(-1) s(-1) for the 2,7-isomer, holding great promise for the field of organic electronics. © 2016 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. The influence of electron irradiation at the various temperatures and annealing on carriers mobility at the low temperatures in neutron transmutation doped gallium arsenide

    International Nuclear Information System (INIS)

    Korshunov, F.P.; Kurilovich, N.F.; Prokhorenko, T.A.; Troshchinskii, V.T.; Shesholko, V.K.

    1999-01-01

    The influence of electron irradiation at the various temperatures and annealing on measured at T=100 K carriers mobility in neutron transmutation doped GaAs have been investigated. It was detected that rate of mobility decreasing with irradiation dose increasing decreases when irradiation temperature increases. It was shown that at the same time it take place the radiation defects creating and their particular or full annealing (in the dependence on irradiation temperature). Radiation stimulated annealing (annealing that take place during irradiation at the elevated temperatures) is more effective than the annealing at the same temperatures that take place after crystals are irradiated at room temperature. It means that any defects annealing during irradiation at elevated temperatures take place at more low temperatures than that during annealing after irradiation at room temperature

  15. Method to quantify the delocalization of electronic states in amorphous semiconductors and its application to assessing charge carrier mobility of p -type amorphous oxide semiconductors

    Science.gov (United States)

    de Jamblinne de Meux, A.; Pourtois, G.; Genoe, J.; Heremans, P.

    2018-01-01

    Amorphous semiconductors are usually characterized by a low charge carrier mobility, essentially related to their lack of long-range order. The development of such material with higher charge carrier mobility is hence challenging. Part of the issue comes from the difficulty encountered by first-principles simulations to evaluate concepts such as the electron effective mass for disordered systems since the absence of periodicity induced by the disorder precludes the use of common concepts derived from condensed matter physics. In this paper, we propose a methodology based on first-principles simulations that partially solves this problem, by quantifying the degree of delocalization of a wave function and of the connectivity between the atomic sites within this electronic state. We validate the robustness of the proposed formalism on crystalline and molecular systems and extend the insights gained to disordered/amorphous InGaZnO4 and Si. We also explore the properties of p -type oxide semiconductor candidates recently reported to have a low effective mass in their crystalline phases [G. Hautier et al., Nat. Commun. 4, 2292 (2013), 10.1038/ncomms3292]. Although in their amorphous phase none of the candidates present a valence band with delocalization properties matching those found in the conduction band of amorphous InGaZnO4, three of the seven analyzed materials show some potential. The most promising candidate, K2Sn2O3 , is expected to possess in its amorphous phase a slightly higher hole mobility than the electron mobility in amorphous silicon.

  16. Origin of high carrier mobility and low residual stress in RF superimposed DC sputtered Al doped ZnO thin film for next generation flexible devices

    Science.gov (United States)

    Kumar, Naveen; Dubey, Ashish; Bahrami, Behzad; Venkatesan, S.; Qiao, Qiquan; Kumar, Mukesh

    2018-04-01

    In this work, the energy and flux of high energetic ions were controlled by RF superimposed DC sputtering process to increase the grain size and suppress grain boundary potential with minimum residual stress in Al doped ZnO (AZO) thin film. AZO thin films were deposited at different RF/(RF + DC) ratios by keeping total power same and were investigated for their electrical, optical, structural and nanoscale grain boundaries potential. All AZO thin film showed high crystallinity and orientation along (002) with peak shift as RF/(RF + DC) ratio increased from 0.0, pure DC, to 1.0, pure RF. This peak shift was correlated with high residual stress in as-grown thin film. AZO thin film grown at mixed RF/(RF + DC) of 0.75 showed high electron mobility, low residual stress and large crystallite size in comparison to other AZO thin films. The nanoscale grain boundary potential was mapped using Kelvin Probe Force Microscopy in all AZO thin film and it was observed that carrier mobility is controlled not only by grains size but also by grain boundary potential. The XPS analysis confirms the variation in oxygen vacancies and zinc interstitials which explain the origin of low grain boundaries potential and high carrier mobility in AZO thin film deposited at 0.75 RF/(RF + DC) ratio. This study proposes a new way to control the grain size and grain boundary potential to further tune the optoelectronic-mechanical properties of AZO thin films for next generation flexible and optoelectronic devices.

  17. Role of dislocations and carrier concentration in limiting the electron mobility of InN films grown by plasma assisted molecular beam epitaxy

    Science.gov (United States)

    Tangi, Malleswararao; De, Arpan; Shivaprasad, S. M.

    2018-01-01

    We report the molecular beam epitaxy growth of device quality InN films on GaN epilayer and nano-wall network (NWN) templates deposited on c-sapphire by varying the film thickness up to 1 μm. The careful experiments are directed towards obtaining high mobility InN layers having a low band gap with improved crystal quality. The dislocation density is quantified by using high resolution X-ray diffraction rocking curve broadening values of symmetric and asymmetric reflections, respectively. We observe that the dislocation density of the InN films grown on GaN NWN is less than that of the films grown on the GaN epilayer. This is attributed to the nanoepitaxial lateral overlayer growth (ELOG) process, where the presence of voids at the interface of InN/GaN NWN prevents the propagation of dislocation lines into the InN epilayers, thereby causing less defects in the overgrown InN films. Thus, this new adaptation of the nano-ELOG growth process enables us to prepare InN layers with high electron mobility. The obtained electron mobility of 2121 cm2/Vs for 1 μm thick InN/GaN NWN is comparable with the literature values of similar thickness InN films. Furthermore, in order to understand the reasons that limit electron mobility, the charge neutrality condition is employed to study the variation of electron mobility as a function of dislocation density and carrier concentration. Overall, this study provides a route to attaining improved crystal quality and electronic properties of InN films.

  18. Mobilities

    DEFF Research Database (Denmark)

    to social networks, personal identities, and our relationship to the built environment. The omnipresence of mobilities within everyday life, high politics, technology, and tourism (to mention but a few) all point to a key insight harnessed by the ‘mobilities turn’. Namely that mobilities is much more than......The world is on the move. This is a widespread understanding by many inhabitants of contemporary society across the Globe. But what does it actually mean? During over one decade the ‘mobilities turn’ within the social sciences have provided a new set of insights into the repercussions of mobilities...... and environmental degradation. The spaces and territories marked by mobilities as well as the sites marked by the bypassing of such are explored. Moreover, the architectural and technological dimensions to infrastructures and sites of mobilities will be included as well as the issues of power, social exclusion...

  19. Negative differential mobility for negative carriers as revealed by space charge measurements on crosslinked polyethylene insulated model cables

    International Nuclear Information System (INIS)

    Teyssedre, G.; Laurent, C.; Vu, T. T. N.

    2015-01-01

    Among features observed in polyethylene materials under relatively high field, space charge packets, consisting in a pulse of net charge that remains in the form of a pulse as it crosses the insulation, are repeatedly observed but without complete theory explaining their formation and propagation. Positive charge packets are more often reported, and the models based on negative differential mobility(NDM) for the transport of holes could account for some charge packets phenomenology. Conversely, NDM for electrons transport has never been reported so far. The present contribution reports space charge measurements by pulsed electroacoustic method on miniature cables that are model of HVDC cables. The measurements were realized at room temperature or with a temperature gradient of 10 °C through the insulation under DC fields on the order 30–60 kV/mm. Space charge results reveal systematic occurrence of a negative front of charges generated at the inner electrode that moves toward the outer electrode at the beginning of the polarization step. It is observed that the transit time of the front of negative charge increases, and therefore the mobility decreases, with the applied voltage. Further, the estimated mobility, in the range 10 −14 –10 −13  m 2  V −1  s −1 for the present results, increases when the temperature increases for the same condition of applied voltage. The features substantiate the hypothesis of negative differential mobility used for modelling space charge packets

  20. Negative differential mobility for negative carriers as revealed by space charge measurements on crosslinked polyethylene insulated model cables

    Science.gov (United States)

    Teyssedre, G.; Vu, T. T. N.; Laurent, C.

    2015-12-01

    Among features observed in polyethylene materials under relatively high field, space charge packets, consisting in a pulse of net charge that remains in the form of a pulse as it crosses the insulation, are repeatedly observed but without complete theory explaining their formation and propagation. Positive charge packets are more often reported, and the models based on negative differential mobility(NDM) for the transport of holes could account for some charge packets phenomenology. Conversely, NDM for electrons transport has never been reported so far. The present contribution reports space charge measurements by pulsed electroacoustic method on miniature cables that are model of HVDC cables. The measurements were realized at room temperature or with a temperature gradient of 10 °C through the insulation under DC fields on the order 30-60 kV/mm. Space charge results reveal systematic occurrence of a negative front of charges generated at the inner electrode that moves toward the outer electrode at the beginning of the polarization step. It is observed that the transit time of the front of negative charge increases, and therefore the mobility decreases, with the applied voltage. Further, the estimated mobility, in the range 10-14-10-13 m2 V-1 s-1 for the present results, increases when the temperature increases for the same condition of applied voltage. The features substantiate the hypothesis of negative differential mobility used for modelling space charge packets.

  1. Photocatalytic hydrogen generation enhanced by band gap narrowing and improved charge carrier mobility in AgTaO3 by compensated co-doping.

    Science.gov (United States)

    Li, Min; Zhang, Junying; Dang, Wenqiang; Cushing, Scott K; Guo, Dong; Wu, Nianqiang; Yin, Penggang

    2013-10-14

    The correlation of the electronic band structure with the photocatalytic activity of AgTaO3 has been studied by simulation and experiments. Doping wide band gap oxide semiconductors usually introduces discrete mid-gap states, which extends the light absorption but has limited benefit for photocatalytic activity. Density functional theory (DFT) calculations show that compensated co-doping in AgTaO3 can overcome this problem by increasing the light absorption and simultaneously improving the charge carrier mobility. N/H and N/F co-doping can delocalize the discrete mid-gap states created by sole N doping in AgTaO3, which increases the band curvature and the electron-to-hole effective mass ratio. In particular, N/F co-doping creates a continuum of states that extend the valence band of AgTaO3. N/F co-doping thus improves the light absorption without creating the mid-gap states, maintaining the necessary redox potentials for water splitting and preventing from charge carrier trapping. The experimental results have confirmed that the N/F-codoped AgTaO3 exhibits a red-shift of the absorption edge in comparison with the undoped AgTaO3, leading to remarkable enhancement of photocatalytic activity toward hydrogen generation from water.

  2. Recovery of synthetic dye from simulated wastewater using emulsion liquid membrane process containing tri-dodecyl amine as a mobile carrier

    Energy Technology Data Exchange (ETDEWEB)

    Othman, N., E-mail: norasikin@cheme.utm.my [Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia); Zailani, S.N.; Mili, N. [Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia)

    2011-12-30

    Highlights: Black-Right-Pointing-Pointer The emulsion liquid membrane process for synthetic reactive dyes recovery was examined. Black-Right-Pointing-Pointer Mobile carriers of tri-dodycylamine and salicyclic acid was used in formulation to remove the reactive dyes from simulated wastewater. Black-Right-Pointing-Pointer Almost 100% of dye was extracted and recovered in receiving phase. Black-Right-Pointing-Pointer An electrical field was used to breakdown the emulsion to separate the liquid membrane and receiving/recovery phase. - Abstract: The extraction of Red 3BS reactive dye from aqueous solution was studied using emulsion liquid membrane (ELM). ELM is one of the processes that have very high potential in treating industrial wastewater consisting of dyes. In this research, Red 3BS reactive dye was extracted from simulated wastewater using tridodecylamine (TDA) as the carrier agent, salicyclic acid (SA) to protonate TDA, sodium chloride as the stripping agent, kerosene as the diluent and SPAN 80 as emulsifier. Experimental parameters investigated were salicyclic acid concentration, extraction time, SPAN 80 concentration, sodium chloride concentration, TDA concentration, agitation speed, homogenizer speed, emulsifying time and treat ratio. The results show almost 100% of Red 3BS was removed and stripped in the receiving phase at the optimum condition in this ELM system. High voltage coalesce was applied to break the emulsion hence, enables recovery of Red 3BS in the receiving phase.

  3. Negative differential mobility for negative carriers as revealed by space charge measurements on crosslinked polyethylene insulated model cables

    Energy Technology Data Exchange (ETDEWEB)

    Teyssedre, G., E-mail: gilbert.teyssedre@laplace.univ-tlse.fr; Laurent, C. [Université de Toulouse, UPS, INPT, LAPLACE (Laboratoire Plasma et Conversion d' Energie), 118 route de Narbonne, F-31062 Toulouse cedex 9 (France); CNRS, LAPLACE, F-31062 Toulouse (France); Vu, T. T. N. [Université de Toulouse, UPS, INPT, LAPLACE (Laboratoire Plasma et Conversion d' Energie), 118 route de Narbonne, F-31062 Toulouse cedex 9 (France); Electric Power University, 235 Hoang Quoc Viet, 10000 Hanoi (Viet Nam)

    2015-12-21

    Among features observed in polyethylene materials under relatively high field, space charge packets, consisting in a pulse of net charge that remains in the form of a pulse as it crosses the insulation, are repeatedly observed but without complete theory explaining their formation and propagation. Positive charge packets are more often reported, and the models based on negative differential mobility(NDM) for the transport of holes could account for some charge packets phenomenology. Conversely, NDM for electrons transport has never been reported so far. The present contribution reports space charge measurements by pulsed electroacoustic method on miniature cables that are model of HVDC cables. The measurements were realized at room temperature or with a temperature gradient of 10 °C through the insulation under DC fields on the order 30–60 kV/mm. Space charge results reveal systematic occurrence of a negative front of charges generated at the inner electrode that moves toward the outer electrode at the beginning of the polarization step. It is observed that the transit time of the front of negative charge increases, and therefore the mobility decreases, with the applied voltage. Further, the estimated mobility, in the range 10{sup −14}–10{sup −13} m{sup 2} V{sup −1} s{sup −1} for the present results, increases when the temperature increases for the same condition of applied voltage. The features substantiate the hypothesis of negative differential mobility used for modelling space charge packets.

  4. Mobiles Robotersystem

    OpenAIRE

    Schmierer, G.; Wolf, A.

    1999-01-01

    DE 19816893 A UPAB: 20000203 NOVELTY - An optical and or acoustic noticeable advertising and or information carrier (10) is fixed permitting detachment in such a manner at the mobile platform (8), that the advertising and or information carrier does not impair the movability of the mobile platform. The advertising is provided at an exposed place on the mobile platform. USE - Advertising or information communication. ADVANTAGE - Advertising or information is imparted in prominent positioning w...

  5. Enhancement of carrier mobility in MoS{sub 2} field effect transistors by a SiO{sub 2} protective layer

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Peng-Zhi; Zhao, Hai-Ming; Cao, Hui-Wen; Wang, Xue-Feng; Pang, Yu; Li, Yu-Xing; Deng, Ning-Qin; Yang, Yi; Ren, Tian-Ling, E-mail: RenTL@tsinghua.edu.cn, E-mail: zhangsh@sz.tsinghua.edu.cn [Institute of Microelectronics and Tsinghua National Laboratory for Information Science and Technology (TNList), Tsinghua University, Beijing 100084 (China); Zhang, Jing [Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Zhang, Guang-Yu [Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); CollaborativeInnovation Center of Quantum Matter, Beijing 100190 (China); Zhang, Sheng, E-mail: RenTL@tsinghua.edu.cn, E-mail: zhangsh@sz.tsinghua.edu.cn [Institute of Microelectronics and Tsinghua National Laboratory for Information Science and Technology (TNList), Tsinghua University, Beijing 100084 (China); The State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Shanghai 200050 (China); Advanced Sensor and Integrated System Lab, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China)

    2016-05-16

    Molybdenum disulfide is a promising channel material for field effect transistors (FETs). In this paper, monolayer MoS{sub 2} grown by chemical vapor deposition (CVD) was used to fabricate top-gate FETs through standard optical lithography. During the fabrication process, charged impurities and interface states are introduced, and the photoresist is not removed cleanly, which both limit the carrier mobility and the source-drain current. We apply a SiO{sub 2} protective layer, which is deposited on the surface of MoS{sub 2}, in order to avoid the MoS{sub 2} directly contacting with the photoresist and the ambient environment. Therefore, the contact property between the MoS{sub 2} and the electrodes is improved, and the Coulomb scattering caused by the charged impurities and the interface states is reduced. Comparing MoS{sub 2} FETs with and without a SiO{sub 2} protective layer, the SiO{sub 2} protective layer is found to enhance the characteristics of the MoS{sub 2} FETs, including transfer and output characteristics. A high mobility of ∼42.3 cm{sup 2}/V s is achieved, which is very large among the top-gate CVD-grown monolayer MoS{sub 2} FETs.

  6. Printed indium gallium zinc oxide transistors. Self-assembled nanodielectric effects on low-temperature combustion growth and carrier mobility.

    Science.gov (United States)

    Everaerts, Ken; Zeng, Li; Hennek, Jonathan W; Camacho, Diana I; Jariwala, Deep; Bedzyk, Michael J; Hersam, Mark C; Marks, Tobin J

    2013-11-27

    Solution-processed amorphous oxide semiconductors (AOSs) are emerging as important electronic materials for displays and transparent electronics. We report here on the fabrication, microstructure, and performance characteristics of inkjet-printed, low-temperature combustion-processed, amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) grown on solution-processed hafnia self-assembled nanodielectrics (Hf-SANDs). TFT performance for devices processed below 300 °C includes >4× enhancement in electron mobility (μFE) on Hf-SAND versus SiO2 or ALD-HfO2 gate dielectrics, while other metrics such as subthreshold swing (SS), current on:off ratio (ION:IOFF), threshold voltage (Vth), and gate leakage current (Ig) are unchanged or enhanced. Thus, low voltage IGZO/SAND TFT operation (IGZO combustion processing leaves the underlying Hf-SAND microstructure and capacitance intact. This work establishes the compatibility and advantages of all-solution, low-temperature fabrication of inkjet-printed, combustion-derived high-mobility IGZO TFTs integrated with self-assembled hybrid organic-inorganic nanodielectrics.

  7. Temperature-dependent field-effect carrier mobility in organic thin-film transistors with a gate SiO2 dielectric modified by H2O2 treatment

    Science.gov (United States)

    Lin, Yow-Jon; Hung, Cheng-Chun

    2018-02-01

    The effect of the modification of a gate SiO2 dielectric using an H2O2 solution on the temperature-dependent behavior of carrier transport for pentacene-based organic thin-film transistors (OTFTs) is studied. H2O2 treatment leads to the formation of Si(-OH) x (i.e., the formation of a hydroxylated layer) on the SiO2 surface that serves to reduce the SiO2 capacitance and weaken the pentacene-SiO2 interaction, thus increasing the field-effect carrier mobility ( µ) in OTFTs. The temperature-dependent behavior of carrier transport is dominated by the multiple trapping model. Note that H2O2 treatment leads to a reduction in the activation energy. The increased value of µ is also attributed to the weakening of the interactions of the charge carriers with the SiO2 dielectric that serves to reduce the activation energy.

  8. Mobility of carriers in the case of diffuse motion in the configuration space of restructuring divacancies in silicon

    International Nuclear Information System (INIS)

    Dolgolenko, A.P.

    2014-01-01

    Calculated temperature dependence of the electron mobility and describes the behavior of holes in high resistance silicon Czochralski grown and float zone melting, after irradiation by fast neutrons reactor and a subsequent isochronous and isothermal annealing. In the framework of the elaborated model of defect clusters was calculated temperature dependence of the concentration of electrons and holes in silicon samples. It is shown that the configuration change divacancies in clusters of defects and in conducting matrix leads to increase in the height of the drift barriers and concentration of long-wave phonons in conducting matrix samples of silicon. It was defined temperature dependence of the height of the drift barriers in the process of ageing at room temperature n-Si

  9. Aminopropyl groups of the functionalized Mobil Crystalline Material 41 as a carrier for controlled diclofenac sodium and piroxicam delivery.

    Science.gov (United States)

    Khodaverdi, Elham; Ahmadi, Mina; Kamali, Hossein; Hadizadeh, Farzin

    2017-01-01

    Synthetic Mobil Crystalline Material 41 (MCM-41) as a mesoporous material and functionalized MCM-41 using aminopropyl groups were studied in order to investigate their ability to encapsulate and to control the release of diclofenac sodium and piroxicam. MCM-41 was synthesized through sol-gel procedure and functionalized with aminopropyl groups. The physicochemical properties of MCM-41 were studied through particle size analysis, infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and carbon-hydrogen-nitrogen analysis. Diclofenac sodium and piroxicam were loaded into the MCM-41 matrix using the filtration and solvent evaporation methods. The drug-loading capacity was determined by ultraviolet, Fourier transform infrared, X-ray diffraction, and Brunauer-Emmett-Teller analysis. According to the results for pure drug release, >57% was released in the 1 st h, but when these drugs were loaded into pure Mobil Crystalline Material 41 (MCM-41) and functionalized MCM-41, the release into the simulated gastrointestinal medium was less, continuous, and slower. The release of piroxicam from functionalized MCM-41 was slower than that from MCM-41 in the simulated intestinal medium because of the formation of electrostatic bonds between piroxicam and the aminopropyl groups of the functionalized MCM-41. However, in the case of diclofenac sodium, there was no significant difference between pure MCM-41 and functionalized MCM-41. The difference between piroxicam and diclofenac sodium was due to the high solubility of diclofenac sodium in the intestinal medium (pH 6.8), which caused more rapid release from the matrixes than for piroxicam. Our findings indicate that, after functionalization of MCM-41, it could offer a good means of delivering controlled diclofenac sodium and piroxicam.

  10. Investigation of carrier density and mobility in microcrystalline silicon alloys using Hall effect and thermopower measurements; Untersuchung der Ladungstraegerkonzentration und -beweglichkeit in mikrokristallinen Siliziumlegierungen mit Hall-Effekt und Thermokraft

    Energy Technology Data Exchange (ETDEWEB)

    Sellmer, Christian

    2012-08-31

    The electronic properties of amorphous and microcrystalline silicon layers in thin-film solar cells significantly affect the efficiency of solar cells. An important property of the individual layer is the electronic transport, which is described by the variables conductivity, photoconductivity, mobility, and carrier concentration. In the past, individual characterization methods were typically used to determine the electronic properties. Using the combination of Hall effect, conductivity, and thermoelectric power measurements additional variables can be derived, such as the effective density of states at the valence and conduction band edge, making a more detailed description of the material possible. To systematically study the electronic properties - in particular carrier mobility and carrier concentration - various series of silicon films are prepared for this work including microcrystalline silicon layers of different doping and crystallinity and a series of silicon films where the Fermi level is moved by irradiation with high energy electrons on one and the same sample. The results show that the transition from amorphous to microcrystalline transport is relatively abrupt. If the electron transport takes place in only amorphous regions, it is marked by the sign anomaly of the Hall effect. If a continuous crystalline path exists, the electronic properties are dominated by the crystalline volume fraction. The results of the measurements of silicon layers are compared with those of microcrystalline silicon carbide samples. Silicon carbide is especially interesting for future applications in thin-film solar cells due to high transparency and high conductivity. It is shown that the effective density of states at the valence and conduction band edge as a function of temperature in p- and n-type microcrystalline silicon and silicon carbide samples largely coincide with those of crystalline silicon or silicon carbide. A square root shaped profile of the density of

  11. Carrier mobility enhancement of nano-crystalline semiconductor films: Incorporation of redox -relay species into the grain boundary interface

    Science.gov (United States)

    Desilva, L. A.; Bandara, T. M. W. J.; Hettiarachchi, B. H.; Kumara, G. R. A.; Perera, A. G. U.; Rajapaksa, R. M. G.; Tennakone, K.

    Dye-sensitized and perovskite solar cells and other nanostructured heterojunction electronic devices require securing intimate electronic contact between nanostructured surfaces. Generally, the strategy is solution phase coating of a hole -collector over a nano-crystalline high-band gap n-type oxide semiconductor film painted with a thin layer of the light harvesting material. The nano-crystallites of the hole - collector fills the pores of the painted oxide surface. Most ills of these devices are associated with imperfect contact and high resistance of the hole conducting layer constituted of nano-crystallites. Denaturing of the delicate light harvesting material forbid sintering at elevated temperatures to reduce the grain boundary resistance. It is found that the interfacial and grain boundary resistance can be significantly reduced via incorporation of redox species into the interfaces to form ultra-thin layers. Suitable redox moieties, preferably bonded to the surface, act as electron transfer relays greatly reducing the film resistance offerring a promising method of enhancing the effective hole mobility of nano-crystalline hole-collectors and developing hole conductor paints for application in nanostructured devices.

  12. Study of carrier mobility of N,N′-diphenyl-N,N′bis(1,1′-biphenyl)-4,4′-diamine (NPB) by transmission line model of impedance spectroscopy

    International Nuclear Information System (INIS)

    Tang, Chao; Xu, Hui; Wang, Xu-Liang; Liu, Wei; Liu, Rui-Lan; Rong, Zhou; Fan, Qu-Li; Huang, Wei

    2013-01-01

    As a powerful method for electrical measurement, impedance spectroscopy and admittance spectroscopy methods began to receive more and more attention in organic electronics research scholars. It demonstrates outstanding advantages especially in the measurement of the mobility of the charge carriers. In this paper, the hole mobility of N,N′-diphenyl-N,N′bis(1,1′-biphenyl)-4,4′-diamine (NPB) was studied by the transmission line model based on impedance spectroscopy. According to energy level of the materials of each layer, a hole-only current device with single-layer structure of indium-tin-oxide(ITO)/NPB/Ag was designed and fabricated, and its Nyquist diagram was measured at different biased voltage. The corresponding transmission line model was proposed according to the device structure and the materials, which was used to the fitting procedure to get the transfer time of the carrier. At last, the carrier mobility was obtained from the transfer time. The results showed that the hole mobility of NPB obtained by transmission line model was in line with the Poole–Freckle model. The zero-field mobility and the pre-exponential factor was further achieved to be 3.9 × 10 −5 cm 2 · V −1 · s −1 and 6.8 × 10 −3 (V/cm) −1/2 , respectively. Moreover, the method can also be easily used for the study of the electron transport properties of the organic semiconductor. - Highlights: • Hole mobility of N,N′-diphenyl-N,N′bis(1,1′-biphenyl)-4,4′-diamine (NPB) was studied by the transmission line model • The results was in line with the Poole-Freckle model • Zero-field mobility and the pre-exponential factor was further achieved

  13. Thermal and Optical Modulation of the Carrier Mobility in OTFTs Based on an Azo-anthracene Liquid Crystal Organic Semiconductor.

    Science.gov (United States)

    Chen, Yantong; Li, Chao; Xu, Xiuru; Liu, Ming; He, Yaowu; Murtaza, Imran; Zhang, Dongwei; Yao, Chao; Wang, Yongfeng; Meng, Hong

    2017-03-01

    One of the most striking features of organic semiconductors compared with their corresponding inorganic counterparts is their molecular diversity. The major challenge in organic semiconductor material technology is creating molecular structural motifs to develop multifunctional materials in order to achieve the desired functionalities yet to optimize the specific device performance. Azo-compounds, because of their special photoresponsive property, have attracted extensive interest in photonic and optoelectronic applications; if incorporated wisely in the organic semiconductor groups, they can be innovatively utilized in advanced smart electronic applications, where thermal and photo modulation is applied to tune the electronic properties. On the basis of this aspiration, a novel azo-functionalized liquid crystal semiconductor material, (E)-1-(4-(anthracen-2-yl)phenyl)-2-(4-(decyloxy)phenyl)diazene (APDPD), is designed and synthesized for application in organic thin-film transistors (OTFTs). The UV-vis spectra of APDPD exhibit reversible photoisomerizaton upon photoexcitation, and the thin films of APDPD show a long-range orientational order based on its liquid crystal phase. The performance of OTFTs based on this material as well as the effects of thermal treatment and UV-irradiation on mobility are investigated. The molecular structure, stability of the material, and morphology of the thin films are characterized by thermal gravimetric analysis (TGA), polarizing optical microscopy (POM), (differential scanning calorimetry (DSC), UV-vis spectroscopy, atomic force microscopy (AFM), and scanning tunneling microscopy (STM). This study reveals that our new material has the potential to be applied in optical sensors, memories, logic circuits, and functional switches.

  14. Vectorisation of agrochemicals via amino acid carriers: influence of the spacer arm structure on the phloem mobility of phenylpyrrole conjugates in the Ricinus system.

    Science.gov (United States)

    Marhadour, Sophie; Wu, Hanxiang; Yang, Wen; Marivingt-Mounir, Cécile; Bonnemain, Jean-Louis; Chollet, Jean-François

    2017-09-01

    Excessive agrochemical use poses significant threats to environmental safety and human health. Reducing pesticide use without reducing yield is necessary for sustainable agriculture. Therefore, we developed a vectorisation strategy to enhance agrochemical delivery through plant amino acid carriers. In addition to a fenpiclonil conjugate recently described, three new amino acid conjugates were synthesised by coupling fenpiclonil to an l-α-amino acid. Phloem mobility of these conjugates, which exhibit different structures of the spacer arm introduced between fenpiclonil and the α-amino acid function, was studied using the Ricinus model. Conjugate L-14, which contains a triazole ring with the shortest amino acid chain, showed the best phloem systemicity among the four conjugates. By contrast, removing the triazole ring in the spacer arm did not improve systemicity. L-14 exhibited phloem systemicity at all reported pH values (pH values from 5.0 to 6.5) of the foliar apoplast, while acidic derivatives of fenpiclonil were translocated only at pH values near 5.0. The conjugates were recognised by a pH-dependent transporter system and translocated at distance in the phloem. They exhibited a broader phloem systemicity than fenpiclonil acidic derivatives within the pH value range of the foliar apoplast. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  15. Two-dimensional n -InSe/p -GeSe(SnS) van der Waals heterojunctions: High carrier mobility and broadband performance

    Science.gov (United States)

    Xia, Cong-xin; Du, Juan; Huang, Xiao-wei; Xiao, Wen-bo; Xiong, Wen-qi; Wang, Tian-xing; Wei, Zhong-ming; Jia, Yu; Shi, Jun-jie; Li, Jing-bo

    2018-03-01

    Recently, constructing van der Waals (vdW) heterojunctions by stacking different two-dimensional (2D) materials has been considered to be effective strategy to obtain the desired properties. Here, through first-principles calculations, we find theoretically that the 2D n -InSe/p -GeSe(SnS) vdW heterojunctions are the direct-band-gap semiconductor with typical type-II band alignment, facilitating the effective separation of photogenerated electron and hole pairs. Moreover, they possess the high optical absorption strength (˜105 ), broad spectrum width, and excellent carrier mobility (˜103c m2V-1s-1 ). Interestingly, under the influences of the interlayer coupling and external electric field, the characteristics of type-II band alignment is robust, while the band-gap values and band offset are tunable. These results indicate that 2D n -InSe/p -GeSe(SnS) heterojunctions possess excellent optoelectronic and transport properties, and thus can become good candidates for next-generation optoelectronic nanodevices.

  16. Radionuclide carrier

    International Nuclear Information System (INIS)

    Hartman, F.A.; Kretschmar, H.C.; Tofe, A.J.

    1978-01-01

    A physiologically acceptable particulate radionuclide carrier is described. It comprises a modified anionic starch derivative with 0.1% to 1.5% by weight of a reducing agent and 1 to 20% by weight of anionic substituents

  17. Carrier Screening

    Science.gov (United States)

    ... How accurate is carrier screening? No test is perfect. In a small number of cases, test results ... in which an egg is removed from a woman’s ovary, fertilized in a laboratory with the man’s ...

  18. The effects of degeneracy of the carrier ensemble on the energy loss rate and the high field mobility characteristics under the conditions of low lattice temperatures

    International Nuclear Information System (INIS)

    Basu, A.; Das, B.; Middya, T.R.; Bhattacharya, D.P.

    2017-01-01

    The rate of loss of energy of the non-equilibrium electrons to the acoustic mode lattice vibration in a degenerate semiconductor is obtained under the condition, when the lattice temperature is low enough, so that the traditional approximations like the elastic nature of the electron-phonon collisions and the truncation of the phonon distribution to the equipartition law are not valid any more. Using the results of the energy loss rate, the non-ohmic mobility is then calculated. Evaluating the loss rate and the non-ohmic mobility in degenerate samples of Si and Ge we find that significant changes in both the characteristics have been effected compared to that in the non-degenerate samples, in the regime of lower energy and for relatively lower fields. The effected changes are more significant the lower the lattice temperature is.

  19. Design and Development of a Mechanical Carrier for Mobile Robot (with rough surface/terrain movement features)- Extension of KINPOE Robot Project for Application at K-1

    International Nuclear Information System (INIS)

    Ahmad, H. W.

    2012-01-01

    During plant (KANUPP) operation, it is difficult or nearly impossible to access and monitor (high) radiation areas where some abnormal condition has to be detected or mitigated. Presence of a surveillance mobile robot will be very useful for such a scenario. This project work is an effort towards the development of a mobile robot that can be used for remote surveillance. A four DOF (degree of freedom) articulated robotic arm, and mobile base is developed. Manipulator is designed using Autodesk inventor, and then fabricated in PIEAS Fabrication Shop. All joints of the manipulator are revolute joints. Maxon DC motors have been used to empower the joints with the help of gears. Spur gear and planetary gear head have been used to increase the torque at joints and to reduce the speed. The report provides complete detail about mechanical design, moreover some casting procedures are also discussed at the end to cast main parts of robot, problems that were faced during the project and their solutions are also discussed in the report. (author)

  20. Mobilities Mobilities

    Directory of Open Access Journals (Sweden)

    César Pompeyo

    2011-12-01

    Full Text Available Urry, John (2007 Mobilities.Oxford: Polity Press.Urry, John (2007 Mobilities.Oxford: Polity Press.John Urry (1946-, profesor en la Universidad de Lancaster, es un sociólogo de sobra conocido y altamente reputado en el panorama internacional de las ciencias sociales. Su dilatada carrera, aparentemente dispersa y diversificada, ha seguido senderos bastante bien definidos dejando tras de sí un catálogo extenso de obras sociológicas de primer nivel. Sus primeros trabajos se centraban en el campo de la teoría social y la filosofía de las ciencias sociales o de la sociología del poder [...

  1. Aircraft Carriers

    DEFF Research Database (Denmark)

    Nødskov, Kim; Kværnø, Ole

    as their purchases of aircraft carrier systems, makes it more than likely that the country is preparing such an acquisition. China has territorial disputes in the South China Sea over the Spratly Islands and is also worried about the security of its sea lines of communications, by which China transports the majority......, submarines, aircraft and helicopters, is not likely to be fully operational and war-capable until 2020, given the fact that China is starting from a clean sheet of paper. The United States of America (USA), the United Kingdom (UK), Russia and India are currently building or have made decisions to build new...

  2. Two-dimensional analytical model of double-gate tunnel FETs with interface trapped charges including effects of channel mobile charge carriers

    Science.gov (United States)

    Xu, Huifang; Dai, Yuehua

    2017-02-01

    A two-dimensional analytical model of double-gate (DG) tunneling field-effect transistors (TFETs) with interface trapped charges is proposed in this paper. The influence of the channel mobile charges on the potential profile is also taken into account in order to improve the accuracy of the models. On the basis of potential profile, the electric field is derived and the expression for the drain current is obtained by integrating the BTBT generation rate. The model can be used to study the impact of interface trapped charges on the surface potential, the shortest tunneling length, the drain current and the threshold voltage for varying interface trapped charge densities, length of damaged region as well as the structural parameters of the DG TFET and can also be utilized to design the charge trapped memory devices based on TFET. The biggest advantage of this model is that it is more accurate, and in its expression there are no fitting parameters with small calculating amount. Very good agreements for both the potential, drain current and threshold voltage are observed between the model calculations and the simulated results. Project supported by the National Natural Science Foundation of China (No. 61376106), the University Natural Science Research Key Project of Anhui Province (No. KJ2016A169), and the Introduced Talents Project of Anhui Science and Technology University.

  3. Hybrid complementary circuits based on p-channel organic and n-channel metal oxide transistors with balanced carrier mobilities of up to 10 cm2/Vs

    KAUST Repository

    Isakov, Ivan

    2016-12-29

    We report the development of hybrid complementary inverters based on p-channel organic and n-channel metal oxide thin-film transistors (TFTs) both processed from solution at <200 °C. For the organic TFTs, a ternary blend consisting of the small-molecule 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene, the polymer indacenodithiophene-benzothiadiazole (CIDT-BT) and the p-type dopant CF was employed, whereas the isotype InO/ZnO heterojunction was used for the n-channel TFTs. When integrated on the same substrate, p- and n-channel devices exhibited balanced carrier mobilities up to 10 cm/Vs. Hybrid complementary inverters based on these devices show high signal gain (>30 V/V) and wide noise margins (70%). The moderate processing temperatures employed and the achieved level of device performance highlight the tremendous potential of the technology for application in the emerging sector of large-area microelectronics.

  4. Hybrid complementary circuits based on p-channel organic and n-channel metal oxide transistors with balanced carrier mobilities of up to 10 cm2/Vs

    KAUST Repository

    Isakov, Ivan; Paterson, Alexandra F.; Solomeshch, Olga; Tessler, Nir; Zhang, Qiang; Li, Jun; Zhang, Xixiang; Fei, Zhuping; Heeney, Martin; Anthopoulos, Thomas D.

    2016-01-01

    We report the development of hybrid complementary inverters based on p-channel organic and n-channel metal oxide thin-film transistors (TFTs) both processed from solution at <200 °C. For the organic TFTs, a ternary blend consisting of the small-molecule 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene, the polymer indacenodithiophene-benzothiadiazole (CIDT-BT) and the p-type dopant CF was employed, whereas the isotype InO/ZnO heterojunction was used for the n-channel TFTs. When integrated on the same substrate, p- and n-channel devices exhibited balanced carrier mobilities up to 10 cm/Vs. Hybrid complementary inverters based on these devices show high signal gain (>30 V/V) and wide noise margins (70%). The moderate processing temperatures employed and the achieved level of device performance highlight the tremendous potential of the technology for application in the emerging sector of large-area microelectronics.

  5. Wafer-scale characterization of carrier dynamics in graphene

    DEFF Research Database (Denmark)

    Buron, Jonas Christian Due; Petersen, Dirch Hjorth; Bøggild, Peter

    2015-01-01

    The electronic properties of single-layer graphene, such as surface conductance, carrier concentration, scattering time and mobility, can be characterized in a noncontact manner by THz time-domain spectroscopy. Standard spectroscopic imaging reveals the AC conductance over large areas with a few...... hundred μm resolution, and spectroscopic imaging on back-gated graphene allows for extraction of both the carrier concentration and the mobility. We find that spatial variations of the conductance of single-layer CVD-grown graphene are predominantly due to variations in mobility rather than in carrier...

  6. Coexistence of Dirac and massive carriers in α-(BEDT-TTF){sub 2}I{sub 3} under hydrostatic pressure

    Energy Technology Data Exchange (ETDEWEB)

    Navarin, Fabien; Tisserond, Emilie [Laboratoire de Physique des Solides, UMR 8502, CNRS-Université Paris-Sud, Orsay F-91405 (France); Auban-Senzier, Pascale, E-mail: pascale.senzier@u-psud.fr [Laboratoire de Physique des Solides, UMR 8502, CNRS-Université Paris-Sud, Orsay F-91405 (France); Mézière, Cécile; Batail, Patrick [MOLTECH-Anjou, UMR 6200, CNRS-Université d' Angers, Bat. K, Angers F-49045 (France); Pasquier, Claude; Monteverde, Miguel [Laboratoire de Physique des Solides, UMR 8502, CNRS-Université Paris-Sud, Orsay F-91405 (France)

    2015-03-01

    We present magnetotransport measurements of α-(BEDT-TTF){sub 2}I{sub 3} crystals under hydrostatic pressure larger than 1.5 GPa where Dirac carriers are present. We show not only the existence of high-mobility Dirac carriers but we also prove experimentally the presence of low-mobility massive carriers, in agreement with band-structure calculations.

  7. Charge mobility modification of semiconducting carbon nanotubes by intrinsic defects

    International Nuclear Information System (INIS)

    Bai, Hongcun; Ma, Yujia; Ma, Jinsuo; Mei, Jingnan; Tong, Yan; Ji, Yongqiang

    2017-01-01

    Charge carrier mobility is a central transport property in nanoscale electronics. Carbon nanotubes (CNTs) are supposed to have high carrier mobility. The preparation methods of CNTs have been greatly improved, but the defects always exist. This work presented first-principle investigations on the charge carrier mobility of carbon nanotubes containing several intrinsic defects. The charge carrier mobilities of zigzag (10, 0) tubes with Stone–Wales, mono vacant and 5/8/5 defects were studied as an example to explore the role of defects. Most carrier mobilities were decreased, but several values of mobility are unexpectedly increased upon the appearance of the defects. This interesting result is discussed based on the changes of the stretching modulus, the effective mass of the carrier and deformation potential constant induced by the defects. (paper)

  8. Charge carrier coherence and Hall effect in organic semiconductors

    Science.gov (United States)

    Yi, H. T.; Gartstein, Y. N.; Podzorov, V.

    2016-01-01

    Hall effect measurements are important for elucidating the fundamental charge transport mechanisms and intrinsic mobility in organic semiconductors. However, Hall effect studies frequently reveal an unconventional behavior that cannot be readily explained with the simple band-semiconductor Hall effect model. Here, we develop an analytical model of Hall effect in organic field-effect transistors in a regime of coexisting band and hopping carriers. The model, which is supported by the experiments, is based on a partial Hall voltage compensation effect, occurring because hopping carriers respond to the transverse Hall electric field and drift in the direction opposite to the Lorentz force acting on band carriers. We show that this can lead in particular to an underdeveloped Hall effect observed in organic semiconductors with substantial off-diagonal thermal disorder. Our model captures the main features of Hall effect in a variety of organic semiconductors and provides an analytical description of Hall mobility, carrier density and carrier coherence factor. PMID:27025354

  9. Charge carrier coherence and Hall effect in organic semiconductors.

    Science.gov (United States)

    Yi, H T; Gartstein, Y N; Podzorov, V

    2016-03-30

    Hall effect measurements are important for elucidating the fundamental charge transport mechanisms and intrinsic mobility in organic semiconductors. However, Hall effect studies frequently reveal an unconventional behavior that cannot be readily explained with the simple band-semiconductor Hall effect model. Here, we develop an analytical model of Hall effect in organic field-effect transistors in a regime of coexisting band and hopping carriers. The model, which is supported by the experiments, is based on a partial Hall voltage compensation effect, occurring because hopping carriers respond to the transverse Hall electric field and drift in the direction opposite to the Lorentz force acting on band carriers. We show that this can lead in particular to an underdeveloped Hall effect observed in organic semiconductors with substantial off-diagonal thermal disorder. Our model captures the main features of Hall effect in a variety of organic semiconductors and provides an analytical description of Hall mobility, carrier density and carrier coherence factor.

  10. Photo-generated carriers lose energy during extraction from polymer-fullerene solar cells

    KAUST Repository

    Melianas, Armantas; Etzold, Fabian; Savenije, Tom J.; Laquai, Fré dé ric; Inganä s, Olle; Kemerink, Martijn

    2015-01-01

    motion is boosted by this process, leading to a time-dependent carrier mobility as confirmed by direct experiments. We identify the time and distance scales relevant for carrier extraction and show that the photo-generated carriers are extracted from

  11. Role of band states and trap states in the electrical properties of organic semiconductors: Hopping versus mobility edge model

    KAUST Repository

    Mehraeen, Shafigh; Coropceanu, Veaceslav; Bré das, Jean-Luc

    2013-01-01

    We compare the merits of a hopping model and a mobility edge model in the description of the effect of charge-carrier concentration on the electrical conductivity, carrier mobility, and Fermi energy of organic semiconductors. We consider the case

  12. Graphene mobility mapping

    DEFF Research Database (Denmark)

    Buron, Jonas Christian Due; Pizzocchero, Filippo; Jepsen, Peter Uhd

    2015-01-01

    Carrier mobility and chemical doping level are essential figures of merit for graphene, and large-scale characterization of these properties and their uniformity is a prerequisite for commercialization of graphene for electronics and electrodes. However, existing mapping techniques cannot directly...... assess these vital parameters in a non-destructive way. By deconvoluting carrier mobility and density from non-contact terahertz spectroscopic measurements of conductance in graphene samples with terahertz-transparent backgates, we are able to present maps of the spatial variation of both quantities over...... graphene indicates dominance by charged scatterers. Unexpectedly, significant variations in mobility rather than doping are the cause of large conductance inhomogeneities, highlighting the importance of statistical approaches when assessing large-area graphene transport properties....

  13. Mobile marketing for mobile games

    OpenAIRE

    Vu, Giang

    2016-01-01

    Highly developed mobile technology and devices enable the rise of mobile game industry and mobile marketing. Hence mobile marketing for mobile game is an essential key for a mobile game success. Even though there are many articles on marketing for mobile games, there is a need of highly understanding mobile marketing strategies, how to launch a mobile campaign for a mobile game. Besides that, it is essential to understand the relationship between mobile advertising and users behaviours. There...

  14. Ultrafast carrier thermalization in lead iodide perovskite probed with two-dimensional electronic spectroscopy.

    Science.gov (United States)

    Richter, Johannes M; Branchi, Federico; Valduga de Almeida Camargo, Franco; Zhao, Baodan; Friend, Richard H; Cerullo, Giulio; Deschler, Felix

    2017-08-29

    In band-like semiconductors, charge carriers form a thermal energy distribution rapidly after optical excitation. In hybrid perovskites, the cooling of such thermal carrier distributions occurs on timescales of about 300 fs via carrier-phonon scattering. However, the initial build-up of the thermal distribution proved difficult to resolve with pump-probe techniques due to the requirement of high resolution, both in time and pump energy. Here, we use two-dimensional electronic spectroscopy with sub-10 fs resolution to directly observe the carrier interactions that lead to a thermal carrier distribution. We find that thermalization occurs dominantly via carrier-carrier scattering under the investigated fluences and report the dependence of carrier scattering rates on excess energy and carrier density. We extract characteristic carrier thermalization times from below 10 to 85 fs. These values allow for mobilities of 500 cm 2  V -1  s -1 at carrier densities lower than 2 × 10 19  cm -3 and limit the time for carrier extraction in hot carrier solar cells.Carrier-carrier scattering rates determine the fundamental limits of carrier transport and electronic coherence. Using two-dimensional electronic spectroscopy with sub-10 fs resolution, Richter and Branchi et al. extract carrier thermalization times of 10 to 85 fs in hybrid perovskites.

  15. Peptide-Carrier Conjugation

    DEFF Research Database (Denmark)

    Hansen, Paul Robert

    2015-01-01

    To produce antibodies against synthetic peptides it is necessary to couple them to a protein carrier. This chapter provides a nonspecialist overview of peptide-carrier conjugation. Furthermore, a protocol for coupling cysteine-containing peptides to bovine serum albumin is outlined....

  16. Air Carrier Traffic Statistics.

    Science.gov (United States)

    2013-11-01

    This report contains airline operating statistics for large certificated air carriers based on data reported to U.S. Department of Transportation (DOT) by carriers that hold a certificate issued under Section 401 of the Federal Aviation Act of 1958 a...

  17. Air Carrier Traffic Statistics.

    Science.gov (United States)

    2012-07-01

    This report contains airline operating statistics for large certificated air carriers based on data reported to U.S. Department of Transportation (DOT) by carriers that hold a certificate issued under Section 401 of the Federal Aviation Act of 1958 a...

  18. Minority carrier diffusion, defects, and localization in InGaAsN, with 2% nitrogen

    International Nuclear Information System (INIS)

    Kurtz, Steven R.; Allerman, A. A.; Seager, C. H.; Sieg, R. M.; Jones, E. D.

    2000-01-01

    Electron and hole transport in compensated InGaAsN (≅2% N) are examined through Hall mobility, photoconductivity, and solar cell photoresponse measurements. Short minority carrier diffusion lengths, photoconductive-response spectra, and doping dependent, thermally activated Hall mobilities reveal a broad distribution of localized states. At this stage of development, lateral carrier transport appears to be limited by large scale (>> mean free path) material inhomogeneities, not a random alloy-induced mobility edge. (c) 2000 American Institute of Physics

  19. Mobile Support For Logistics

    Science.gov (United States)

    2016-03-01

    support wireless capabilities, such as Wi-Fi or LTE -based 4G cellular infrastructures, into the DOD’s enterprise software, GCSS-MC could be a large...fielded mobile devices through ViaSat Inc. ViaSat’s goal is to provide secure communications over 3G/4G/ LTE cellular and Wi-Fi networks, secure...or commercial carrier network. While these measures are not all encompassing for protecting mobile devices, they are a ways that drastically improve

  20. High Charge-Carrier Mobility of 2.5 cm(2) V(-1) s(-1) from a Water-Borne Colloid of a Polymeric Semiconductor via Smart Surfactant Engineering.

    Science.gov (United States)

    Cho, Jangwhan; Cheon, Kwang Hee; Ahn, Hyungju; Park, Kwang Hun; Kwon, Soon-Ki; Kim, Yun-Hi; Chung, Dae Sung

    2015-10-07

    Semiconducting polymer nanoparticles dispersed in water are synthesized by a novel method utilizing non-ionic surfactants. By developing a smart surfactant engineering technique involving a selective post-removal process of surfactants, an unprecedentedly high mobility of 2.51 cm(2) V(-1) s(-1) from a water-borne colloid is demonstrated for the first time. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Imaging ballistic carrier trajectories in graphene using scanning gate microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Morikawa, Sei; Masubuchi, Satoru [Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505 (Japan); Dou, Ziwei; Wang, Shu-Wei; Smith, Charles G.; Connolly, Malcolm R., E-mail: mrc61@cam.ac.uk [Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE (United Kingdom); Watanabe, Kenji; Taniguchi, Takashi [National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044 (Japan); Machida, Tomoki, E-mail: tmachida@iis.u-tokyo.ac.jp [Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505 (Japan); Institute for Nano Quantum Information Electronics, University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505 (Japan)

    2015-12-14

    We use scanning gate microscopy to map out the trajectories of ballistic carriers in high-mobility graphene encapsulated by hexagonal boron nitride and subject to a weak magnetic field. We employ a magnetic focusing geometry to image carriers that emerge ballistically from an injector, follow a cyclotron path due to the Lorentz force from an applied magnetic field, and land on an adjacent collector probe. The local electric field generated by the scanning tip in the vicinity of the carriers deflects their trajectories, modifying the proportion of carriers focused into the collector. By measuring the voltage at the collector while scanning the tip, we are able to obtain images with arcs that are consistent with the expected cyclotron motion. We also demonstrate that the tip can be used to redirect misaligned carriers back to the collector.

  2. High mobility emissive organic semiconductor

    Science.gov (United States)

    Liu, Jie; Zhang, Hantang; Dong, Huanli; Meng, Lingqiang; Jiang, Longfeng; Jiang, Lang; Wang, Ying; Yu, Junsheng; Sun, Yanming; Hu, Wenping; Heeger, Alan J.

    2015-01-01

    The integration of high charge carrier mobility and high luminescence in an organic semiconductor is challenging. However, there is need of such materials for organic light-emitting transistors and organic electrically pumped lasers. Here we show a novel organic semiconductor, 2,6-diphenylanthracene (DPA), which exhibits not only high emission with single crystal absolute florescence quantum yield of 41.2% but also high charge carrier mobility with single crystal mobility of 34 cm2 V−1 s−1. Organic light-emitting diodes (OLEDs) based on DPA give pure blue emission with brightness up to 6,627 cd m−2 and turn-on voltage of 2.8 V. 2,6-Diphenylanthracene OLED arrays are successfully driven by DPA field-effect transistor arrays, demonstrating that DPA is a high mobility emissive organic semiconductor with potential in organic optoelectronics. PMID:26620323

  3. Terahertz wafer-scale mobility mapping of graphene on insulating substrates without a gate

    DEFF Research Database (Denmark)

    Buron, Jonas Due; Mackenzie, David M. A.; Petersen, Dirch Hjorth

    2015-01-01

    We demonstrate wafer-scale, non-contact mapping of essential carrier transport parameters, carrier mobility (mu(drift)), carrier density (N-S), DC sheet conductance (sigma(dc)), and carrier scattering time (tau(SC)) in CVD graphene, using spatially resolved terahertz time-domain conductance...

  4. Trustworthy execution on mobile devices

    CERN Document Server

    Vasudevan, Amit; Newsome, James

    2013-01-01

    This brief considers the various stakeholders in today's mobile device ecosystem, and analyzes why widely-deployed hardware security primitives on mobile device platforms are inaccessible to application developers and end-users. Existing proposals are also evaluated for leveraging such primitives, and proves that they can indeed strengthen the security properties available to applications and users, without reducing the properties currently enjoyed by OEMs and network carriers. Finally, this brief makes recommendations for future research that may yield practical and deployable results.

  5. Improved process control, lowered costs and reduced risks through the use of non-destructive mobility and sheet carrier density measurements on GaAs and GaN wafers

    Science.gov (United States)

    Nguyen, D.; Hogan, K.; Blew, A.; Cordes, M.

    2004-12-01

    Improved process control, lowered costs and reduced risks can be realized through the use of non-destructive mobility and sheet charge density measurements during the fabrication of GaAs and GaN wafers. The results from this microwave-based technique are shown to agree with destructive van der Pauw Hall testing results to within ±5%. In addition, it has the ability to map wafer uniformity and provide separated 2DEG data for thick cap or multi-layered structures. As a result, this technique provides an efficient and cost-effective alternative to current process control metrology methods, while providing the user with important process control data.

  6. 77 FR 35336 - Privacy and Security of Information Stored on Mobile Communications Devices

    Science.gov (United States)

    2012-06-13

    ... made available to a carrier by the customer solely by virtue of the carrier-customer relationship,'' a... mobile wireless services providers with respect to customer information stored on their users' mobile... practices of mobile wireless service providers with respect to customer information stored on their users...

  7. Duchenne muscular dystrophy carriers

    International Nuclear Information System (INIS)

    Matsumura, K.; Nakano, I.

    1989-01-01

    By means of magnetic resonance imaging (MRI), the proton spin-lattice relaxation times (T1 values) of the skeletal muscles were measured in Duchenne muscular dystrophy (DMD) carriers and normal controls. The bound water fraction (BWF) was calculated from the T1 values obtained, according to the fast proton diffusion model. In the DMD carriers, T1 values of the gluteus maximus and quadriceps femoris muscles were significantly higher, and BWFs of these muscles were significantly lower than in normal control. Degenerative muscular changes accompanied by interstitial edema were presumed responsible for this abnormality. No correlation was observed between the muscle T1 and serum creatine kinase values. The present study showed that MRI could be a useful method for studying the dynamic state of water in both normal and pathological skeletal muscles. Its possible utility for DMD carrier detection was discussed briefly. (orig.)

  8. Photo-generated carriers lose energy during extraction from polymer-fullerene solar cells

    KAUST Repository

    Melianas, Armantas

    2015-11-05

    In photovoltaic devices, the photo-generated charge carriers are typically assumed to be in thermal equilibrium with the lattice. In conventional materials, this assumption is experimentally justified as carrier thermalization completes before any significant carrier transport has occurred. Here, we demonstrate by unifying time-resolved optical and electrical experiments and Monte Carlo simulations over an exceptionally wide dynamic range that in the case of organic photovoltaic devices, this assumption is invalid. As the photo-generated carriers are transported to the electrodes, a substantial amount of their energy is lost by continuous thermalization in the disorder broadened density of states. Since thermalization occurs downward in energy, carrier motion is boosted by this process, leading to a time-dependent carrier mobility as confirmed by direct experiments. We identify the time and distance scales relevant for carrier extraction and show that the photo-generated carriers are extracted from the operating device before reaching thermal equilibrium.

  9. Asymmetric Carrier Random PWM

    DEFF Research Database (Denmark)

    Mathe, Laszlo; Lungeanu, Florin; Rasmussen, Peter Omand

    2010-01-01

    index. The flat motor current spectrum generates an acoustical noise close to the white noise, which may improve the acoustical performance of the drive. The new carrier wave is easy to implement digitally, without employing any external circuits. The modulation method can be used in open, as well...

  10. Willis H Carrier

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 17; Issue 2. Willis H. Carrier - Father of Air Conditioning. R V Simha. General Article Volume 17 Issue 2 February 2012 pp 117-138. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/017/02/0117-0138 ...

  11. Comparison of mobility extraction methods based on field-effect measurements for graphene

    Directory of Open Access Journals (Sweden)

    Hua Zhong

    2015-05-01

    Full Text Available Carrier mobility extraction methods for graphene based on field-effect measurements are explored and compared according to theoretical analysis and experimental results. A group of graphene devices with different channel lengths were fabricated and measured, and carrier mobility is extracted from those electrical transfer curves using three different methods. Accuracy and applicability of those methods were compared. Transfer length method (TLM can obtain accurate density dependent mobility and contact resistance at relative high carrier density based on data from a group of devices, and then can act as a standard method to verify other methods. As two of the most popular methods, direct transconductance method (DTM and fitting method (FTM can extract mobility easily based on transfer curve of a sole graphene device. DTM offers an underestimated mobility at any carrier density owing to the neglect of contact resistances, and the accuracy can be improved through fabricating field-effect transistors with long channel and good contacts. FTM assumes a constant mobility independent on carrier density, and then can obtain mobility, contact resistance and residual density stimulations through fitting a transfer curve. However, FTM tends to obtain a mobility value near Dirac point and then overestimates carrier mobility of graphene. Comparing with the DTM and FTM, TLM could offer a much more accurate and carrier density dependent mobility, that reflects the complete properties of graphene carrier mobility.

  12. Sealed substrate carrier for electroplating

    Science.gov (United States)

    Ganti, Kalyana Bhargava [Fremont, CA

    2012-07-17

    One embodiment relates to a substrate carrier for use in electroplating a plurality of substrates. The substrate carrier includes a non-conductive carrier body on which the substrates are held, and conductive lines are embedded within the carrier body. A conductive bus bar is embedded into a top side of the carrier body and is conductively coupled to the conductive lines. A thermoplastic overmold covers a portion of the bus bar, and there is a plastic-to-plastic bond between the thermoplastic overmold and the non-conductive carrier body. Other embodiments, aspects and features are also disclosed.

  13. Mobile Learning Using Mobile Phones

    Science.gov (United States)

    Vicente, Paula

    2013-01-01

    The participation in mobile learning programs is conditioned by having/using mobile communication technology. Those who do not have or use such technology cannot participate in mobile learning programs. This study evaluates who are the most likely participants of mobile learning programs by examining the demographic profile and mobile phone usage…

  14. Enhancing Charge Carrier Lifetime in Metal Oxide Photoelectrodes through Mild Hydrogen Treatment

    KAUST Repository

    Jang, Ji-Wook; Friedrich, Dennis; Mü ller, Sö nke; Lamers, Marlene; Hempel, Hannes; Lardhi, Sheikha F.; Cao, Zhen; Harb, Moussab; Cavallo, Luigi; Heller, René ; Eichberger, Rainer; van de Krol, Roel; Abdi, Fatwa F.

    2017-01-01

    and are relatively cheap, are particularly interesting, but high efficiency is still hindered by the poor carrier transport properties (i.e., carrier mobility and lifetime). Here, a mild hydrogen treatment is introduced to bismuth vanadate (BiVO4), which is one

  15. Staging Mobilities / Designing Mobilities

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    2015-01-01

    , and systems 'hosting' these multiple and complex mobilities are designed and how they are staging these in terms of their physical layout. By analysing specific cases of ‘mobilities design’ related to the four modes of moving; Walk, Bike, Train, and Car, the book uncover important and until now neglected...... is more than movement between point A and B. It explores how the movement of people, goods, information, and signs influences human understandings of self, other and the built environment. Moving towards a new understanding of the relationship between movement, interaction and environments, the project...

  16. Study of Charge Carrier Transport in GaN Sensors

    Science.gov (United States)

    Gaubas, Eugenijus; Ceponis, Tomas; Kuokstis, Edmundas; Meskauskaite, Dovile; Pavlov, Jevgenij; Reklaitis, Ignas

    2016-01-01

    Capacitor and Schottky diode sensors were fabricated on GaN material grown by hydride vapor phase epitaxy and metal-organic chemical vapor deposition techniques using plasma etching and metal deposition. The operational characteristics of these devices have been investigated by profiling current transients and by comparing the experimental regimes of the perpendicular and parallel injection of excess carrier domains. Profiling of the carrier injection location allows for the separation of the bipolar and the monopolar charge drift components. Carrier mobility values attributed to the hydride vapor phase epitaxy (HVPE) GaN material have been estimated as μe = 1000 ± 200 cm2/Vs for electrons, and μh = 400 ± 80 cm2/Vs for holes, respectively. Current transients under injection of the localized and bulk packets of excess carriers have been examined in order to determine the surface charge formation and polarization effects. PMID:28773418

  17. Mobility management in mobile IP

    Science.gov (United States)

    Medidi, Sirisha; Golshani, Forouzan

    2002-07-01

    There is an emerging interest in integrating mobile wireless communication with the Internet based on the Ipv6 technology. Many issues introduced by the mobility of users arise when such an integration is attempted. This paper addresses the problem of mobility management, i.e., that of tracking the current IP addresses of mobile terminals and sustaining active IP connections as mobiles move. The paper presents some architectural and mobility management options for integrating wireless access to the Internet. We then present performance results for Mobile IPv4, route optimization and Mobile IPv6.

  18. Motor carrier evaluation program

    International Nuclear Information System (INIS)

    Portsmouth, James

    1992-01-01

    The U.S. Department of Energy-Headquarters (DOE-HQ), Transportation Management Program (TMP) has the overall responsibility to provide a well-managed transportation program for the safe, efficient, and economical transportation of DOE-owned materials. The DOE-TMP has established an excellent safety record in the transportation of hazardous materials including radioactive materials and radioactive wastes. This safety record can be maintained only through continued diligence and sustained effort on the part of the DOE-TMP, its field offices, and the contractors' organizations. Key elements in the DOE'S effective hazardous and radioactive materials shipping program are (1) integrity of packages, (2) strict adherence to regulations and procedures, (3) trained personnel, (4) complete management support, and (5) use of the best commercial carriers. The DOE Motor Carrier Evaluation Program was developed to better define the criteria and methodology needed to identify motor carriers for use in the transportation of Highway Route Controlled Quantities (HRCQ), Truck Load (TL) quantities of radioactive materials, hazardous materials and waste. (author)

  19. Carrier transport uphill. I. General

    DEFF Research Database (Denmark)

    Rosenberg, T; Wilbrandt, W

    1963-01-01

    A quantitative treatment of a carrier pump operating with two carrier forms C and Z is presented. Asymmetric metabolic reactions are assumed to transform Z into C on one and C into Z on the other side of the membrane, establishing a carrier cycle. The kinetical consequences of this mechanism...

  20. Recombination in liquid filled ionisation chambers with multiple charge carrier species: Theoretical and numerical results

    International Nuclear Information System (INIS)

    Aguiar, P.; González-Castaño, D.M.; Gómez, F.; Pardo-Montero, J.

    2014-01-01

    Liquid-filled ionisation chambers (LICs) are used in radiotherapy for dosimetry and quality assurance. Volume recombination can be quite important in LICs for moderate dose rates, causing non-linearities in the dose rate response of these detectors, and needs to be corrected for. This effect is usually described with Greening and Boag models for continuous and pulsed radiation respectively. Such models assume that the charge is carried by two different species, positive and negative ions, each of those species with a given mobility. However, LICs operating in non-ultrapure mode can contain different types of electronegative impurities with different mobilities, thus increasing the number of different charge carriers. If this is the case, Greening and Boag models can be no longer valid and need to be reformulated. In this work we present a theoretical and numerical study of volume recombination in parallel-plate LICs with multiple charge carrier species, extending Boag and Greening models. Results from a recent publication that reported three different mobilities in an isooctane-filled LIC have been used to study the effect of extra carrier species on recombination. We have found that in pulsed beams the inclusion of extra mobilities does not affect volume recombination much, a behaviour that was expected because Boag formula for charge collection efficiency does not depend on the mobilities of the charge carriers if the Debye relationship between mobilities and recombination constant holds. This is not the case in continuous radiation, where the presence of extra charge carrier species significantly affects the amount of volume recombination. - Highlights: • Analytical extension of Greening and Boag theories to multiple charge carriers. • Detailed numerical study of process of volume recombination in LICs. • Recombination in pulsed beams is independent of number and mobilities of carriers. • Multiple charge carriers have a significant effect in continuous

  1. Mobile Election

    OpenAIRE

    Long, Elena; Lovitskii, Vladimir; Thrasher, Michael; Traynor, David

    2009-01-01

    Mobile phones have the potential of fostering political mobilisation. There is a significant political power in mobile technology. Like the Internet, mobile phones facilitate communication and rapid access to information. Compared to the Internet, however, mobile phone diffusion has reached a larger proportion of the population in most countries, and thus the impact of this new medium is conceivably greater. There are now more mobile phones in the UK than there are people (ave...

  2. Mobile Advertising

    OpenAIRE

    Alamuri, Lavanya

    2009-01-01

    The aim of this project was to get an understanding of how companies adopt mobile as an advertising medium. The literature review aided in framing a draft of the factors that affect mobile advertising adoption and possible forms of mobile advertising. Considering the scope of the thesis work, branding strategy, service costs, personalization and privacy and platform were considered to be the factors that could affect the mobile advertising adoption. A few possible forms on mobile device we...

  3. Maintainable substrate carrier for electroplating

    Science.gov (United States)

    Chen, Chen-An [Milpitas, CA; Abas, Emmanuel Chua [Laguna, PH; Divino, Edmundo Anida [Cavite, PH; Ermita, Jake Randal G [Laguna, PH; Capulong, Jose Francisco S [Laguna, PH; Castillo, Arnold Villamor [Batangas, PH; Ma,; Xiaobing, Diana [Saratoga, CA

    2012-07-17

    One embodiment relates to a substrate carrier for use in electroplating a plurality of substrates. The carrier includes a non-conductive carrier body on which the substrates are placed and conductive lines embedded within the carrier body. A plurality of conductive clip attachment parts are attached in a permanent manner to the conductive lines embedded within the carrier body. A plurality of contact clips are attached in a removable manner to the clip attachment parts. The contact clips hold the substrates in place and conductively connecting the substrates with the conductive lines. Other embodiments, aspects and features are also disclosed.

  4. Autonomous component carrier selection

    DEFF Research Database (Denmark)

    Garcia, Luis Guilherme Uzeda; Pedersen, Klaus; Mogensen, Preben

    2009-01-01

    management and efficient system operation. Due to the expected large number of user-deployed cells, centralized network planning becomes unpractical and new scalable alternatives must be sought. In this article, we propose a fully distributed and scalable solution to the interference management problem...... in local areas, basing our study case on LTE-Advanced. We present extensive network simulation results to demonstrate that a simple and robust interference management scheme, called autonomous component carrier selection allows each cell to select the most attractive frequency configuration; improving...... the experience of all users and not just the few best ones; while overall cell capacity is not compromised....

  5. Mobilities Design

    DEFF Research Database (Denmark)

    Lanng, Ditte Bendix; Wind, Simon; Jensen, Ole B.

    2017-01-01

    Mobilities comprise a large part of our world and everyday lives, and the mobilities spaces in which we travel are ubiquitous. Yet, ordinary mobilities spaces – such as parking lots, pedestrian tunnels, and road lay-bys – tend to be criticized as typologies that lack consideration for the people...... who use them and for their wider social, aesthetic, cultural, and ecological agency in the city. This is clearly not an unambiguous characterization. But from it follows an urgency to re-examine unheeded mobilities spaces and extend demands of their agency beyond standards of technical efficiency....... This article draws on the recent “mobilities turn” in social science to support such re-examination of mobilities spaces. In social-scientific mobilities research, mobilities are considered the departure point for understanding the socio-material world in which we live. Mobilities are regarded as far more than...

  6. On the correct interpretation of the low voltage regime in intrinsic single-carrier devices.

    Science.gov (United States)

    Röhr, Jason A; Kirchartz, Thomas; Nelson, Jenny

    2017-05-24

    We discuss the approach of determining the charge-carrier density of a single-carrier device by combining Ohm's law and the Mott-Gurney law. We show that this approach is seldom valid, due to the fact that whenever Ohm's law is applicable the Mott-Gurney law is usually not, and vice versa. We do this using a numerical drift-diffusion solver to calculate the current density-voltage curves and the charge-carrier density, with increasing doping concentration. As this doping concentration is increased to very large values, using Ohm's law becomes a sensible way of measuring the product of mobility and doping density in the sample. However, in the high-doping limit, the current is no longer governed by space-charge and it will no longer be possible to determine the charge-carrier mobility using the Mott-Gurney law. This leaves the value for the mobility as an unknown in the mobility-doping density product in Ohm's law. We also show that, when the charge-carrier mobility for an intrinsic semiconductor is known in advance, the carrier density is underestimated up to many orders of magnitude if Ohm's law is used. We finally seek to establish a window of conditions where the two methods can be combined to yield reasonable results.

  7. On the correct interpretation of the low voltage regime in intrinsic single-carrier devices

    International Nuclear Information System (INIS)

    Röhr, Jason A; Nelson, Jenny; Kirchartz, Thomas

    2017-01-01

    We discuss the approach of determining the charge-carrier density of a single-carrier device by combining Ohm’s law and the Mott–Gurney law. We show that this approach is seldom valid, due to the fact that whenever Ohm’s law is applicable the Mott–Gurney law is usually not, and vice versa. We do this using a numerical drift-diffusion solver to calculate the current density–voltage curves and the charge-carrier density, with increasing doping concentration. As this doping concentration is increased to very large values, using Ohm’s law becomes a sensible way of measuring the product of mobility and doping density in the sample. However, in the high-doping limit, the current is no longer governed by space-charge and it will no longer be possible to determine the charge-carrier mobility using the Mott–Gurney law. This leaves the value for the mobility as an unknown in the mobility-doping density product in Ohm’s law. We also show that, when the charge-carrier mobility for an intrinsic semiconductor is known in advance, the carrier density is underestimated up to many orders of magnitude if Ohm’s law is used. We finally seek to establish a window of conditions where the two methods can be combined to yield reasonable results. (paper)

  8. Mobile Workforce, Mobile Technology, Mobile Threats

    International Nuclear Information System (INIS)

    Garcia, J.

    2015-01-01

    Mobile technologies' introduction into the world of safeguards business processes such as inspection creates tremendous opportunity for novel approaches and could result in a number of improvements to such processes. Mobile applications are certainly the wave of the future. The success of the application ecosystems has shown that users want full fidelity, highly-usable, simple purpose applications with simple installation, quick responses and, of course, access to network resources at all times. But the counterpart to opportunity is risk, and the widespread adoption of mobile technologies requires a deep understanding of the threats and vulnerabilities inherent in mobile technologies. Modern mobile devices can be characterized as small computers. As such, the threats against computing infrastructure apply to mobile devices. Meanwhile, the attributes of mobile technology that make it such an obvious benefit over traditional computing platforms all have elements of risk: pervasive, always-on networking; diverse ecosystems; lack of centralized control; constantly shifting technological foundations; intense competition among competitors in the marketplace; the scale of the installation base (from millions to billions); and many more. This paper will explore the diverse and massive environment of mobile, the number of attackers and vast opportunities for compromise. The paper will explain how mobile devices prove valuable targets to both advanced and persistent attackers as well as less-skilled casual hackers. Organized crime, national intelligence agencies, corporate espionage are all part of the landscape. (author)

  9. Mobile nuclear power systems

    International Nuclear Information System (INIS)

    Andersson, B.

    1988-11-01

    This report is meant to present a general survey of the mobile nuclear power systems and not a detailed review of their technical accomplishments. It is based in published material mainly up to 1987. Mobile nuclear power systems are of two fundamentally different kinds: nuclear reactors and isotopic generators. In the reactors the energy comes from nuclear fission and in the isotopic generators from the radioactive decay of suitable isotopes. The reactors are primarily used as power sourves on board nuclear submarines and other warships but have also been used in the space and in remote places. Their thermal power has ranged from 30 kWth (in a satellite) to 175 MWth (on board an aircraft carrier). Isotopic generators are suitable only for small power demands and have been used on board satellites and spaceprobes, automatic weatherstations, lighthouses and marine installations for navigation and observation. (author)

  10. Mobilities Design

    DEFF Research Database (Denmark)

    Jensen, Ole B.; Lanng, Ditte Bendix

    Contemporary society is marked and defined by the ways in which mobile goods, bodies, vehicles, objects, and data are organized, moved and staged. On the background of the ‘mobilities turn’ (e.g. Cresswell 2006, Urry 2007) this book articulates a new and emerging research field, namely that of ‘m......Contemporary society is marked and defined by the ways in which mobile goods, bodies, vehicles, objects, and data are organized, moved and staged. On the background of the ‘mobilities turn’ (e.g. Cresswell 2006, Urry 2007) this book articulates a new and emerging research field, namely...... that of ‘mobilities design’. The book revolves around the following research question: How are design decisions and interventions staging mobilities? It builds upon the Staging Mobilities model (Jensen 2013) in an explorative inquiry into the problems and potentials of the design of mobilities. The exchange value...

  11. Mobile economy

    OpenAIRE

    Turowski, Klaus

    2004-01-01

    Mobile economy : Transaktionen, Prozesse, Anwendungen und Dienste ; 4. Workshop Mobile Commerce, 02.-03. Februar 2004, Univ. Augsburg / K. Turowski ... (Hrsg.). - Bonn : Ges. für Informatik, 2004. - 189 S. : Ill., graph. Darst. - (GI-Edition : Proceedings ; 42)

  12. Mobile marketing

    OpenAIRE

    Gause, Matěj

    2012-01-01

    The goal of bachelor's thesis on the theme "Mobile marketing" is to outline its development and why is this new phenomen so important for all modern companies around the world. The work is not about simple description of mobile marketing media but it vividly informs about the latest trends and news from the world of mobile apps and games. It presents the most successful mobile apps which registered more than billion downloads and from their unique characteristics it unveils great potential of...

  13. Mobile marketing

    OpenAIRE

    KLEČKOVÁ, Zuzana

    2013-01-01

    The main aim of this thesis was to provide a comprehensive overview of the mobile marketing and analyze selected campaigns of Czech mobile marketing in comparison to world successful campaigns. The research contained studying of available literature about the theme to gain general knowledge about the issue. The theoretical part of the thesis contains predominantly various definitions of mobile marketing and its tools, advantages of these tools and some information about Mobile Marketing Assoc...

  14. Staging Mobilities

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    and lived as people are “staging themselves” (from below). Staging mobilities is a dynamic process between “being staged” (for example, being stopped at traffic lights) and the “mobile staging” of interacting individuals (negotiating a passage on the pavement). Staging Mobilities is about the fact...

  15. Subversive Mobilities

    DEFF Research Database (Denmark)

    Thelle, Mikkel

    2013-01-01

    The article approaches mobility through a cultural history of urban conflict. Using a case of “The Copenhagen Trouble,“ a series of riots in the Danish capital around 1900, a space of subversive mobilities is delineated. These turn-of-the-century riots points to a new pattern of mobile gathering...

  16. LIQUIFIED NATURAL GAS (LNG CARRIERS

    Directory of Open Access Journals (Sweden)

    Daniel Posavec

    2010-12-01

    Full Text Available Modern liquefied natural gas carriers are double-bottom ships classified according to the type of LNG tank. The tanks are specially designed to store natural gas cooled to -161°C, the boiling point of methane. Since LNG is highly flammable, special care must be taken when designing and operating the ship. The development of LNG carriers has begun in the middle of the twentieth century. LNG carrier storage space has gradually grown to the current maximum of 260000 m3. There are more than 300 LNG carriers currently in operation (the paper is published in Croatian.

  17. Renewable energy carriers: Hydrogen or liquid air/nitrogen?

    International Nuclear Information System (INIS)

    Li Yongliang; Chen Haisheng; Zhang Xinjing; Tan Chunqing; Ding Yulong

    2010-01-01

    The world's energy demand is met mainly by the fossil fuels today. The use of such fuels, however, causes serious environmental issues, including global warming, ozone layer depletion and acid rains. A sustainable solution to the issues is to replace the fossil fuels with renewable ones. Implementing such a solution, however, requires overcoming a number of technological barriers including low energy density, intermittent supply and mobility of the renewable energy sources. A potential approach to overcoming these barriers is to use an appropriate energy carrier, which can store, transport and distribute energy. The work to be reported in this paper aims to assess and compare a chemical energy carrier, hydrogen, with a physical energy carrier, liquid air/nitrogen, and discuss potential applications of the physical carrier. The ocean energy is used as an example of the renewable energy sources in the work. The assessment and comparison are carried out in terms of the overall efficiency, including production, storage/transportation and energy extraction. The environmental impact, waste heat recovery and safety issues are also considered. It is found that the physical energy carrier may be a better alternative to the chemical energy carrier under some circumstances, particularly when there are waste heat sources.

  18. Multiple carrier transport in N-face indium nitride

    International Nuclear Information System (INIS)

    Koblmueller, Gregor; Gallinat, Chad S.; Speck, James S.; Umana-Membreno, Gilberto A.; Nener, Brett D.; Parish, Giacinta; Fehlberg, Tamara B.

    2008-01-01

    We present temperature (20-300 K) dependent multi-carrier measurements of electron species in N-face indium nitride. N-face InN samples were grown to different thicknesses (500-2000 nm) via plasma-assisted molecular beam epitaxy on C-face SiC substrates. Surface and bulk electron transport properties were extracted using a quantitative mobility spectrum analysis. Mobility of both bulk and surface electron species increase with film thickness. The temperature dependence of the mobility of both species differs to that of In-polar samples studied previously, while the mobility of surface electrons is more than twice that of In-polar samples with only a slight corresponding reduction in sheet concentration. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  19. Mobile Probes in Mobile Learning

    DEFF Research Database (Denmark)

    Ørngreen, Rikke; Blomhøj, Ulla; Duvaa, Uffe

    In this paper experiences from using mobile probes in educational design of a mobile learning application is presented. The probing process stems from the cultural probe method, and was influenced by qualitative interview and inquiry approaches. In the project, the mobile phone was not only acting...... as an agent for acquiring empirical data (as the situation in hitherto mobile probe settings) but was also the technological medium for which data should say something about (mobile learning). Consequently, not only the content of the data but also the ways in which data was delivered and handled, provided...... a valuable dimension for investigating mobile use. The data was collected at the same time as design activities took place and the collective data was analysed based on user experience goals and cognitive processes from interaction design and mobile learning. The mobile probe increased the knowledge base...

  20. Mobile Semiotics

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    2013-01-01

    This chapter aims to understand the mobile condition of contemporary life with a particular view to the signifying dimension of the environment and its ‘readability’. The chapter explores the potentials of semiotics and its relationship to the new mobilities literature. What takes place...... is a ‘mobile sense making’ where signs and materially situated meanings connect to the moving human body and thus create particular challenges and complexities of making sense of the world. The chapter includes notions of mobility systems and socio-technical networks in order to show how a ‘semiotic layer’ may...... work to afford or restrict mobile practices....

  1. Mobile Lexicography

    DEFF Research Database (Denmark)

    Køhler Simonsen, Henrik

    2014-01-01

    Users are already mobile, but the question is to which extent knowledge-based dictionary apps are designed for the mobile user situation. The objective of this article is to analyse the characteristics of the mobile user situation and to look further into the stationary user situation and the mob......Users are already mobile, but the question is to which extent knowledge-based dictionary apps are designed for the mobile user situation. The objective of this article is to analyse the characteristics of the mobile user situation and to look further into the stationary user situation...... and the mobile user situation. The analysis is based on an empirical survey involving ten medical doctors and a monolingual app designed to support cognitive lexicographic functions, cf. (Tarp 2006:61-64). In test A the doctors looked up five medical terms while sitting down at a desk and in test B the doctors...

  2. Mobility Divides

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    Contemporary mobilities are cultural and social manifestations, and the mobile practices in the everyday life of billions of humans are re-configuring senses of place, self, other and relationships to the built environment. The way ‘mobile situations’ are staged in designed and built environments......’ in the everyday life and cast light on how design and ‘materialities of mobilites’ are creating differential mobilities across societies, social networks, and communities of practices.......Contemporary mobilities are cultural and social manifestations, and the mobile practices in the everyday life of billions of humans are re-configuring senses of place, self, other and relationships to the built environment. The way ‘mobile situations’ are staged in designed and built environments...

  3. Mobile Semiotics - signs and mobilities

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    a potential for mobilities studies if the awareness of seeing the environment as a semiotic layer and system can be sensitized to the insights of the ‘mobilities turn’. Empirically the paper tentatively explores the usefulness of a mobile semiotics approach to cases such as street signage, airport design...

  4. Liquid Crystalline Perylene diimides : Architecture and Charge Carrier Mobilities

    NARCIS (Netherlands)

    Struijk, C.W.; Sieval, A.B.; Dakhorst, J.E.J.; Dijk, van M.; Kimkes, P.; Koehorst, R.B.M.; Donker, H.

    2000-01-01

    The phase behavior of three N-alkyl-substituted perylene diimide derivatives is examined by differential scanning calorimetry and polarized optical microscopy. The occurrence of multiple phase transitions indicates several crystalline and several liquid crystalline phases. X-ray diffraction

  5. High Charge Carrier Mobility Polymers for Organic Transistors

    OpenAIRE

    Erdmann, Tim

    2017-01-01

    I) Introduction p-Conjugated polymers inherently combine electronic properties of inorganic semiconductor crystals and material characteristics of organic plastics due to their special molecular design. This unique combination has led to developing new unconventional optoelectronic technologies and, further, resulted in the evolution of semiconducting polymers (SCPs) as fundamental components for novel electronic devices, such as organic field-effect transistors (OFETs), organic light-emit...

  6. Investigation of carrier mobility degradation effects on MOSFET leakage simulations

    CSIR Research Space (South Africa)

    Twala, B

    2016-01-01

    Full Text Available silicon germanium-on-insulator p-MOS FinFETs,” 72nd Device Research Conference 2014, pp. 183-184. [7] P. Damas, X. Le-Roux, D. Marris-Morini, E. Cassan, L.Vivien “Strained silicon for photonics applications,” 17th International Conference...

  7. The energy carrier hydrogen

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    The potential of hydrogen to be used as a clean fuel for the production of heat and power, as well as for the propulsion of aeroplanes and vehicles, is described, in particular for Germany. First, attention is paid to the application of hydrogen as a basic material for the (petro)chemical industry, as an indirect energy source for (petro)chemical processes, and as a direct energy source for several purposes. Than the importance of hydrogen as an energy carrier in a large-scale application of renewable energy sources is discussed. Next an overview is given of new and old hydrogen production techniques from fossil fuels, biomass, or the electrolysis of water. Energetic applications of hydrogen in the transportation sector and the production of electric power and heat are mentioned. Brief descriptions are given of techniques to store hydrogen safely. Finally attention is paid to hydrogen research in Germany. Two hydrogen projects, in which Germany participates, are briefly dealt with: the Euro-Quebec project (production of hydrogen by means of hydropower), and the HYSOLAR project (hydrogen production by means of solar energy). 18 figs., 1 tab., 7 refs

  8. Ultrafast carrier dynamics in Br.sup.+./sup.-bombarded InP studied by time-resolved terahertz spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Němec, Hynek; Fekete, Ladislav; Kadlec, Filip; Kužel, Petr

    2008-01-01

    Roč. 78, č. 23 (2008), 235206/1-235206/7 ISSN 1098-0121 R&D Projects: GA MŠk LC512 Institutional research plan: CEZ:AV0Z10100520 Keywords : InP * carrier lifetime * carrier mobility * ultrafast * ion-bombardment * terahertz Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.322, year: 2008

  9. Mobile Clouds

    DEFF Research Database (Denmark)

    Fitzek, Frank; Katz, Marcos

    A mobile cloud is a cooperative arrangement of dynamically connected communication nodes sharing opportunistic resources. In this book, authors provide a comprehensive and motivating overview of this rapidly emerging technology. The book explores how distributed resources can be shared by mobile...... users in very different ways and for various purposes. The book provides many stimulating examples of resource-sharing applications. Enabling technologies for mobile clouds are also discussed, highlighting the key role of network coding. Mobile clouds have the potential to enhance communications...... performance, improve utilization of resources and create flexible platforms to share resources in very novel ways. Energy efficient aspects of mobile clouds are discussed in detail, showing how being cooperative can bring mobile users significant energy saving. The book presents and discusses multiple...

  10. Mobilities Design

    DEFF Research Database (Denmark)

    Jensen, Ole B.; Lanng, Ditte Bendix; Wind, Simon

    2016-01-01

    In this paper, we identify the nexus between design (architecture, urban design, service design, etc.) and mobilities as a new and emerging research field. In this paper, we apply a “situational mobilities” perspective and take point of departure in the pragmatist question: “What design decisions...... and interventions affords this particular mobile situation?” The paper presents the contours of an emerging research agenda within mobilities research. The advent of “mobilities design” as an emerging research field points towards a critical interest in the material as well as practical consequences of contemporary......-making. The paper proposes that increased understanding of the material affordances facilitated through design provides important insight to planning and policymaking that at times might be in risk of becoming too detached from the everyday life of the mobile subject within contemporary mobilities landscapes....

  11. Mobil marketing

    OpenAIRE

    Engelová, Kateřina

    2006-01-01

    Mobil marketing - reklama a podpora prodeje prostřednictvím mobilních telefonů. Technologické a kulturní předpoklady vzniku tohoto odvětví. Mobil marketing a marketingový mix, možnosti synergie. Nástroje mobil marketingu - reklamní SMS a MMS, lokační služby, soutěže, ankety a hlasování, věrnostní systémy, mobilní obsah. Subjekty mobil marketingu. M-komerce. Využití pro podnikové aplikace.

  12. LIQUIFIED NATURAL GAS (LNG) CARRIERS

    OpenAIRE

    Daniel Posavec; Katarina Simon; Matija Malnar

    2010-01-01

    Modern liquefied natural gas carriers are double-bottom ships classified according to the type of LNG tank. The tanks are specially designed to store natural gas cooled to -161°C, the boiling point of methane. Since LNG is highly flammable, special care must be taken when designing and operating the ship. The development of LNG carriers has begun in the middle of the twentieth century. LNG carrier storage space has gradually grown to the current maximum of 260000 m3. There are more than 300 L...

  13. Impact of carriers in oral absorption

    DEFF Research Database (Denmark)

    Gram, Luise Kvisgaard; Rist, Gerda Marie; Lennernäs, Hans

    2009-01-01

    Carriers may mediate the permeation across enterocytes for drug substances being organic anions. Carrier mediated permeation for the organic anions estrone-3-sulfate (ES) and glipizide across Caco-2 cells were investigated kinetically, and interactions on involved carriers evaluated. Initial...

  14. 7 CFR 35.4 - Carrier.

    Science.gov (United States)

    2010-01-01

    ... AND PLUMS Definitions § 35.4 Carrier. Carrier means any common or private carrier, including, but not being limited to, trucks, rail, airplanes, vessels, tramp or chartered steamers, whether carrying for...

  15. Basic Stand Alone Carrier Line Items PUF

    Data.gov (United States)

    U.S. Department of Health & Human Services — This release contains the Basic Stand Alone (BSA) Carrier Line Items Public Use Files (PUF) with information from Medicare Carrier claims. The CMS BSA Carrier Line...

  16. Mobile phones and mobile communication

    DEFF Research Database (Denmark)

    Ling, Richard; Donner, Jonathan

    With staggering swiftness, the mobile phone has become a fixture of daily life in almost every society on earth. In 2007, the world had over 3 billion mobile subscriptions. Prosperous nations boast of having more subscriptions than people. In the developing world, hundreds of millions of people who...... could never afford a landline telephone now have a mobile number of their own. With a mobile in our hand many of us feel safer, more productive, and more connected to loved ones, but perhaps also more distracted and less involved with things happening immediately around us. Written by two leading...... researchers in the field, this volume presents an overview of the mobile telephone as a social and cultural phenomenon. Research is summarized and made accessible though detailed descriptions of ten mobile users from around the world. These illustrate popular debates, as well as deeper social forces at work...

  17. Contention aware mobility prediction routing for intermittently connected mobile networks

    KAUST Repository

    Elwhishi, Ahmed; Ho, Pin-Han; Shihada, Basem

    2013-01-01

    This paper introduces a novel multi-copy routing protocol, called predict and forward (PF), for delay tolerant networks, which aims to explore the possibility of using mobile nodes as message carriers for end-to-end delivery of the messages. With PF, the message forwarding decision is made by manipulating the probability distribution of future inter-contact and contact durations based on the network status, including wireless link condition and nodal buffer availability. In particular, PF is based on the observations that the node mobility behavior is semi-deterministic and could be predicted once there is sufficient mobility history information. We implemented the proposed protocol and compared it with a number of existing encounter-based routing approaches in terms of delivery delay, delivery ratio, and the number of transmissions required for message delivery. The simulation results show that PF outperforms all the counterpart multi-copy encounter-based routing protocols considered in the study.

  18. Contention aware mobility prediction routing for intermittently connected mobile networks

    KAUST Repository

    Elwhishi, Ahmed

    2013-04-26

    This paper introduces a novel multi-copy routing protocol, called predict and forward (PF), for delay tolerant networks, which aims to explore the possibility of using mobile nodes as message carriers for end-to-end delivery of the messages. With PF, the message forwarding decision is made by manipulating the probability distribution of future inter-contact and contact durations based on the network status, including wireless link condition and nodal buffer availability. In particular, PF is based on the observations that the node mobility behavior is semi-deterministic and could be predicted once there is sufficient mobility history information. We implemented the proposed protocol and compared it with a number of existing encounter-based routing approaches in terms of delivery delay, delivery ratio, and the number of transmissions required for message delivery. The simulation results show that PF outperforms all the counterpart multi-copy encounter-based routing protocols considered in the study.

  19. Ambipolar carrier transport properties and molecular packing structure of octahexyl-substituted copper phthalocyanine

    Science.gov (United States)

    Watanabe, Ken; Watanabe, Koichi; Tohnai, Norimitsu; Itani, Hiromichi; Shimizu, Yo; Fujii, Akihiko; Ozaki, Masanori

    2018-04-01

    The charge carrier mobility of a solution-processable low-molecular-weight organic semiconductor material, i.e., 1,4,8,11,15,18,22,25-octahexylphthalocyanine copper complex (C6PcCu), was investigated by the time-of-flight technique. The anomalous ambipolar carrier mobility was discussed from the viewpoint of the molecular packing structure, which was clarified by single-crystal X-ray structure analysis. In the comparison between the molecular packing structures of C6PcCu and its metal-free-type homologue, it was found that the difference in carrier mobility originates from the rotation of the molecule, which is caused by the steric hindrance due to the introduction of a center metal and the interpenetration of the nonperipheral alkyl chains.

  20. Mobility activation in thermally deposited CdSe thin films

    Indian Academy of Sciences (India)

    Effect of illumination on mobility has been studied from the photocurrent decay characteristics of thermally evaporated CdSe thin films deposited on suitably cleaned glass substrate held at elevated substrate temperatures. The study indicates that the mobilities of the carriers of different trap levels are activated due to the ...

  1. Urban Mobility

    DEFF Research Database (Denmark)

    2017-01-01

    This anthology is the proceedings publication from the 2015 NAF Symposium in Malmö, Sweden. The aim of the 2015 NAF Symposium “Urban Mobility – Architectures, Geographies and Social Space” was to facilitate a cross-disciplinary discussion on urban mobility in which the juxtaposition of different...

  2. Urban Mobility

    DEFF Research Database (Denmark)

    2017-01-01

    This anthology is the proceedings publication from the 2015 NAF Symposium in Malmö, Sweden. The aim of the 2015 NAF Symposium “Urban Mobility – Architectures, Geographies and Social Space” was to facilitate a cross-disciplinary discussion on urban mobility in which the juxtaposition of different ...

  3. Mobile phone

    International Nuclear Information System (INIS)

    2009-01-01

    Almost the entire Norwegian population has cell phone. The usefulness of the cell phone is great, but can use a mobile phone to health or discomfort? How can exposure be reduced? NRPA follows research and provides advice on mobile phone use. (AG)

  4. Motor carrier evaluation program plan

    International Nuclear Information System (INIS)

    Portsmouth, J.H.; Maxwell, J.E.; Boness, G.O.; Rice, L.E.

    1991-04-01

    The US Department of Energy (DOE) Transportation Management Program (TMP) has established a program to assist the DOE field offices and their contractors in evaluating the motor carriers used to transport DOE-owned hazardous and radioactive materials. This program was initiated to provide the DOE field offices with the tools necessary to help ensure, during this period of motor carrier deregulation, that only highly qualified carriers transport radioactive and hazardous commodities for the DOE. This program will assist DOE in maintaining their excellent performance record in the safe transportation of hazardous commodities. The program was also developed in response to public concern surrounding the transportation of hazardous materials. Representatives of other federal agencies, states, and tribal governments, as well as the news media, have expressed concern about the selection and qualification of carriers engaged in the transportation of Highway Route-Controlled Quantities (HRCQ) and Truckload (TL) quantities of radioactive material for the DOE. 8 refs

  5. Solute carrier transporters: Pharmacogenomics research ...

    African Journals Online (AJOL)

    Aghogho

    2010-12-27

    Dec 27, 2010 ... This paper reviews the solute carrier transporters and highlights the fact that there is much to be learnt from .... transporters, drug targets, effect or proteins and meta- ... basolateral or apical plasma membrane of polarized cells,.

  6. Carrier transport in amorphous silicon utilizing picosecond photoconductivity

    Science.gov (United States)

    Johnson, A. M.

    1981-08-01

    The development of a high-speed electronic measurement capability permitted the direct observation of the transient photoresponse of amorphous silicon (a-Si) with a time resolution of approximately 10ps. This technique was used to measure the initial mobility of photogenerated (2.1eV) free carriers in three types of a-Si having widely different densities of structural defects (i.e., as prepared by: (1) RF glow discharge (a-Si:H); (2) chemical vapor deposition; and (3) evaporation in ultra-high vacuum). In all three types of a-Si, the same initial mobility of approximately 1 cu cm/Vs at room temperature was found. This result tends to confirm the often-made suggestion that the free carrier mobility is determined by the influence of shallow states associated with the disorder in the random atomic network, and is an intrinsic property of a-Si which is unaffected by the method of preparation. The rate of decay of the photocurrent correlates with the density of structural defects and varies from 4ps to 200ps for the three types of a-Si investigated. The initial mobility of a-Si:H was found to be thermally activated. The possible application of extended state transport controlled by multiple trapping and small polaron formation is discussed.

  7. Control of charge carrier dynamics in disordered conjugated polymers

    Energy Technology Data Exchange (ETDEWEB)

    Hertel, Dirk [Physical Chemistry, University of Cologne, Luxemburgerstr. 116, 50939 Cologne, Germany, (Germany)

    2011-07-01

    We developed a new method to probe charge carrier mobility on ultrafast time scale. It is based on electric field induced second harmonic generation. The method is applied to prototypical amorphous conjugated polymers of the polyphenylene- and polyfluorene-type. Typically the carrier mobility in these organic polymers decreases with time in a power law fashion from about 1 cm{sup 2}Vs{sup -1} at 1 ps to its stationary value of about 10{sup -6} cm{sup 2}Vs{sup -1} in hundreds of ns. The dynamics of the mobility is discussed. It is shown, that in nanoscale devices the macroscopic mobility is not adequate to describe charge transport. We study the influence of disorder, morphology and temperature on ultrafast transport. At early times the transport is dominated by tunneling and disorder plays already an essential role. Comparison of transient photocurrents with Monte-Carlo simulation reveals that on-chain transport has to be invoked to rationalize our results. The hopping rates for intrachain transport are much larger compared with interchain transport. The results give access to essential transport properties for the development of advanced theoretical models and may help to design improved solar cells.

  8. Intensive mobilities

    DEFF Research Database (Denmark)

    Vannini, Phillip; Bissell, David; Jensen, Ole B.

    with fieldwork conducted in Canada, Denmark and Australia to develop our understanding of the experiential politics of long distance workers. Rather than focusing on the extensive dimensions of mobilities that are implicated in patterns and trends, our paper turns to the intensive dimensions of this experience......This paper explores the intensities of long distance commuting journeys as a way of exploring how bodily sensibilities are being changed by the mobilities that they undertake. The context of this paper is that many people are travelling further to work than ever before owing to a variety of factors...... which relate to transport, housing and employment. Yet we argue that the experiential dimensions of long distance mobilities have not received the attention that they deserve within geographical research on mobilities. This paper combines ideas from mobilities research and contemporary social theory...

  9. Designing Mobilities

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    are often still not engaged with in a sufficiently manner. Often social sciences keep distance to the physical and material as if the social was still to be understood as a realm separate of technology, architecture, and design (for a critique of this see; Latour 2005 and Urry 2000). This paper takes point......Within the so-called ‘mobilities turn’ (Adey 2010; Cresswell 2006; Urry 2007) much research has taken place during the last decade bringing mobilities into the centre of sociological analysis. However, the materiality and spatiality of artefacts, infrastructures, and sites hosting mobilities...... of departure in the sociological perspective termed ‘Staging Mobilities’ (Jensen 2013a) and utilizes this as an analytical frame for exploring cases of mobility design. The paper put focus on how the material shape, design and architectures of technologies, spaces and sites influence mobilities practices...

  10. Mobile probes

    DEFF Research Database (Denmark)

    Ørngreen, Rikke; Jørgensen, Anna Neustrup; Noesgaard, Signe Schack

    2016-01-01

    A project investigating the effectiveness of a collection of online resources for teachers' professional development used mobile probes as a data collection method. Teachers received questions and tasks on their mobile in a dialogic manner while in their everyday context as opposed...... to in an interview. This method provided valuable insight into the contextual use, i.e. how did the online resource transfer to the work practice. However, the research team also found that mobile probes may provide the scaffolding necessary for individual and peer learning at a very local (intra-school) community...... level. This paper is an initial investigation of how the mobile probes process proved to engage teachers in their efforts to improve teaching. It also highlights some of the barriers emerging when applying mobile probes as a scaffold for learning....

  11. Mobilities Design

    DEFF Research Database (Denmark)

    Jensen, Ole B.; Lanng, Ditte Bendix

    2016-01-01

    of life’ for billions of people in the everyday life. This paper is structured in three parts. After the general introduction we present the mobilities theory perspective of ‘staging mobilities’ and connects this to the empirical phenomenon of parking lots and their design. The paper ends in section three......Contemporary society is marked and defined by the ways in which mobile goods, bodies, vehicles, objects, and data are organized, moved and staged. On the backgound of the ‘mobilities turn’ (for short review paper on this see; Sheller 2011, Vannini 2010) this paper proposes a further development...... of the perspective in the direction of a material and design oriented turn. In order to fulfill this purpose we articulate a new and emerging research field, namely that of ‘mobilities design’. In our understanding time has come to articulate ‘Mobilities Design’ as a dedicated research field in and of its own...

  12. Mobile Lexicography

    DEFF Research Database (Denmark)

    Køhler Simonsen, Henrik

    2015-01-01

    are already mobile – but lexicography is not yet fully ready for the mobile challenge, mobile users and mobile user situations. The article is based on empirical data from two surveys comprising 10 medical doctors, who were asked to look up five medical substances with the medical dictionary app Medicin.......dk and five students, who were asked to look up five terms with the dictionary app Gyldendal Engelsk-Dansk. The empirical data comprise approximately 15 hours of recordings of user behavior, think-aloud data and interview data. The data indicate that there is still much to be done in this area...... and that lexicographic innovation is needed. A new type of users, new user situations and new access methods call for new lexicographic solutions, and this article proposes a six-pointed hexagram model, which can be used during dictionary app design to lexicographically calibrate the six dimensions in mobile...

  13. Restricted Mobilities

    DEFF Research Database (Denmark)

    Nielsen, Mette; Lassen, Claus

    2012-01-01

    communities and shopping centres through mobility lenses. The article shows how different mobility systems enable and restrict the public access to private-public spaces, and it points out that proprietary communities create an unequal potential for human movement and access in the city. The main argument......Privatisation of public spaces in the contemporary city has increased during the last decades but only few studies have approached this field from a mobility perspective. Therefore the article seeks to rectify this by exploring two Australian examples of private spaces in the city; gated...... and stratification mechanisms. In conclusion the article therefore suggests that future urban research and planning also needs a mobile understanding of spaces in the cities and how different mobility systems play an important role to sustain the exclusiveness that often characterises the private/public spaces...

  14. Mobility Work

    DEFF Research Database (Denmark)

    Bardram, Jakob Eyvind; Bossen, Claus

    2005-01-01

    We posit the concept of Mobility Work to describe efforts of moving about people and things as part of accomplishing tasks. Mobility work can be seen as a spatial parallel to the concept of articulation work proposed by the sociologist Anselm Strauss. Articulation work describes efforts of coordi....../or resources. To accomplish their work, actors have to make the right configuration of these four aspects emerge.......We posit the concept of Mobility Work to describe efforts of moving about people and things as part of accomplishing tasks. Mobility work can be seen as a spatial parallel to the concept of articulation work proposed by the sociologist Anselm Strauss. Articulation work describes efforts...... of coordination necessary in cooperative work, but focuses, we argue, mainly on the temporal aspects of cooperative work. As a supplement, the concept of mobility work focuses on the spatial aspects of cooperative work. Whereas actors seek to diminish the amount of articulation work needed in collaboration...

  15. Mobility Challenges

    DEFF Research Database (Denmark)

    Jensen, Ole B.; Lassen, Claus

    2011-01-01

    This article takes point of departure in the challenges to understand the importance of contemporary mobility. The approach advocated is a cross-disciplinary one drawing on sociology, geography, urban planning and design, and cultural studies. As such the perspective is to be seen as a part...... of the so-called ‘mobility turn’ within social science. The perspective is illustrative for the research efforts at the Centre for Mobility and Urban Studies (C-MUS), Aalborg University. The article presents the contours of a theoretical perspective meeting the challenges to research into contemporary urban...... mobilities. In particular the article discusses 1) the physical city, its infrastructures and technological hardware/software, 2) policies and planning strategies for urban mobility and 3) the lived everyday life in the city and the region....

  16. Sustainable Mobility

    DEFF Research Database (Denmark)

    Kjærulff, Aslak Aamot

    This paper combines strands of mobilities theory and planning theory, and develops a qualitative approach to look across emerging planning practices. By actively following 8 Danish urban and transport planners, over the course of 2 years, we learn how their practices have changed, inspired...... by mobility management, a concept aiming to reduce carbon emissions from transportation in western societies. The article focuses on how municipal planners formulate the role of mobility management activities organized around private companies, and how their practices are connected to wider ideas on planning....

  17. Enhancing Charge Carrier Lifetime in Metal Oxide Photoelectrodes through Mild Hydrogen Treatment

    KAUST Repository

    Jang, Ji-Wook

    2017-08-25

    Widespread application of solar water splitting for energy conversion is largely dependent on the progress in developing not only efficient but also cheap and scalable photoelectrodes. Metal oxides, which can be deposited with scalable techniques and are relatively cheap, are particularly interesting, but high efficiency is still hindered by the poor carrier transport properties (i.e., carrier mobility and lifetime). Here, a mild hydrogen treatment is introduced to bismuth vanadate (BiVO4), which is one of the most promising metal oxide photoelectrodes, as a method to overcome the carrier transport limitations. Time-resolved microwave and terahertz conductivity measurements reveal more than twofold enhancement of the carrier lifetime for the hydrogen-treated BiVO4, without significantly affecting the carrier mobility. This is in contrast to the case of tungsten-doped BiVO4, although hydrogen is also a donor type dopant in BiVO4. The enhancement in carrier lifetime is found to be caused by significant reduction of trap-assisted recombination, either via passivation or reduction of deep trap states related to vanadium antisite on bismuth or vanadium interstitials according to density functional theory calculations. Overall, these findings provide further insights on the interplay between defect modulation and carrier transport in metal oxides, which benefit the development of low-cost, highly-efficient solar energy conversion devices.

  18. 29 CFR 1201.1 - Carrier.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 4 2010-07-01 2010-07-01 false Carrier. 1201.1 Section 1201.1 Labor Regulations Relating to Labor (Continued) NATIONAL MEDIATION BOARD DEFINITIONS § 1201.1 Carrier. The term carrier includes any express company, sleeping car company, carrier by railroad, subject to the Interstate Commerce Act...

  19. Low-cost carriers fare competition effect

    NARCIS (Netherlands)

    Carmona Benitez, R.B.; Lodewijks, G.

    2010-01-01

    This paper examines the effects that low-cost carriers (LCC’s) produce when entering new routes operated only by full-service carriers (FSC’s) and routes operated by low-cost carriers in competition with full-service carriers. A mathematical model has been developed to determine what routes should

  20. 47 CFR 22.409 - Developmental authorization for a new Public Mobile Service or technology.

    Science.gov (United States)

    2010-10-01

    ... Mobile Service or technology. 22.409 Section 22.409 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES PUBLIC MOBILE SERVICES Developmental Authorizations § 22.409 Developmental authorization for a new Public Mobile Service or technology. The FCC may grant applications for...

  1. Bacterial Carriers for Glioblastoma Therapy

    Directory of Open Access Journals (Sweden)

    Nalini Mehta

    2017-03-01

    Full Text Available Treatment of aggressive glioblastoma brain tumors is challenging, largely due to diffusion barriers preventing efficient drug dosing to tumors. To overcome these barriers, bacterial carriers that are actively motile and programmed to migrate and localize to tumor zones were designed. These carriers can induce apoptosis via hypoxia-controlled expression of a tumor suppressor protein p53 and a pro-apoptotic drug, Azurin. In a xenograft model of human glioblastoma in rats, bacterial carrier therapy conferred a significant survival benefit with 19% overall long-term survival of >100 days in treated animals relative to a median survival of 26 days in control untreated animals. Histological and proteomic analyses were performed to elucidate the safety and efficacy of these carriers, showing an absence of systemic toxicity and a restored neural environment in treated responders. In the treated non-responders, proteomic analysis revealed competing mechanisms of pro-apoptotic and drug-resistant activity. This bacterial carrier opens a versatile avenue to overcome diffusion barriers in glioblastoma by virtue of its active motility in extracellular space and can lead to tailored therapies via tumor-specific expression of tumoricidal proteins.

  2. Mobility spectrum analytical approach for intrinsic band picture of Ba(FeAs)2

    Science.gov (United States)

    Huynh, K. K.; Tanabe, Y.; Urata, T.; Heguri, S.; Tanigaki, K.; Kida, T.; Hagiwara, M.

    2014-09-01

    Unconventional high temperature superconductivity as well as three-dimensional bulk Dirac cone quantum states arising from the unique d-orbital topology have comprised an intriguing research area in physics. Here we apply a special analytical approach using a mobility spectrum, in which the carrier number is conveniently described as a function of mobility without any hypothesis, both on the types and the numbers of carriers, for the interpretations of longitudinal and transverse electric transport of high quality single crystal Ba(FeAs)2 in a wide range of magnetic fields. We show that the majority carriers are accommodated in large parabolic hole and electron pockets with very different topology as well as remarkably different mobility spectra, whereas the minority carriers reside in Dirac quantum states with the largest mobility as high as 70,000 cm2(Vs)-1. The deduced mobility spectra are discussed and compared to the reported sophisticated first principle band calculations.

  3. Carrier heating in disordered conjugated polymers in electric field

    Energy Technology Data Exchange (ETDEWEB)

    Vukmirovic, Nenad; Wang, Lin-Wang

    2010-01-26

    The electric field dependence of charge carrier transport and the effect of carrier heating in disordered conjugated polymers were investigated. A parameter-free multiscale methodology consisting of classical molecular dynamics simulation for the generation of the atomic structure, large system electronic structure and electron-phonon coupling constants calculations and the procedure for extracting the bulk polymer mobility, was used. The results suggested that the mobility of a fully disordered poly(3-hexylthiophene) (P3HT) polymer increases with electric field which is consistent with the experimental results on samples of regiorandom P3HT and different from the results on more ordered regioregular P3HT polymers, where the opposite trend is often observed at low electric fields. We calculated the electric field dependence of the effective carrier temperature and showed however that the effective temperature cannot be used to replace the joint effect of temperature and electric field, in contrast to previous theoretical results from phenomenological models. Such a difference was traced to originate from the use of simplified Miller-Abrahams hopping rates in phenomenological models in contrast to our considerations that explicitly take into account the electronic state wave functions and the interaction with all phonon modes.

  4. A possible high-mobility signal in bulk MoTe2: Temperature independent weak phonon decay

    Directory of Open Access Journals (Sweden)

    Titao Li

    2016-11-01

    Full Text Available Layered transition metal dichalcogenides (TMDs have attracted great attention due to their non-zero bandgap for potential application in high carrier mobility devices. Recent studies demonstrate that the carrier mobility of MoTe2 would decrease by orders of magnitude when used for few-layer transistors. As phonon scattering has a significant influence on carrier mobility of layered material, here, we first reported temperature-dependent Raman spectra of bulk 2H-MoTe2 from 80 to 300 K and discovered that the phonon lifetime of both E12g and A1g vibration modes are independent with temperature. These results were explained by the weak phonon decay in MoTe2. Our results imply the existence of a carrier mobility higher than the theoretical value in intrinsic bulk 2H-MoTe2 and the feasibility to obtain MoTe2-based transistors with sufficiently high carrier mobility.

  5. Structural vs. intrinsic carriers: contrasting effects of cation chemistry and disorder on ionic conductivity in pyrochlores

    International Nuclear Information System (INIS)

    Perriot, Romain; Uberuaga, Blas P.

    2015-01-01

    We use molecular dynamics simulations to investigate the role of cation disorder on oxygen diffusion in Gd 2 Zr 2 O 7 (GZO) and Gd 2 Ti 2 O 7 (GTO) pyrochlores, a class of complex oxides which contain a structural vacancy relative to the basic fluorite structure. The introduction of disorder has distinct effects depending on the chemistry of the material, increasing the mobility of structural carriers by up to four orders of magnitude in GZO. In contrast, in GTO, there is no mobility at zero or low disorder on the ns timescale, but higher disorder liberates the otherwise immobile carriers, allowing diffusion with rates comparable to GZO for the fully disordered material. Here, we show that the cation disorder enhances the diffusivity by both increasing the concentration of mobile structural carriers and their individual mobility. The disorder also influences the diffusion in materials containing intrinsic carriers, such as additional vacancies VO or oxygen interstitials OI. And while in ordered GZO and GTO the contribution of the intrinsic carriers dominates the overall diffusion of oxygen, OI in GZO contributes along with structural carriers, and the total diffusion rate can be calculated by assuming simple additive contributions from the two sources. Although the disorder in the materials with intrinsic defects usually enhances the diffusivity as in the defect-free case, in low concentrations, cation antisites AB or BA, where A = Gd and B = Zr or Ti, can act as traps for fast intrinsic defects. The trapping results in a lowering of the diffusivity, and causes a non-monotonic behavior of the diffusivity with disorder. Conversely, in the case of slow intrinsic defects, the main effect of the disorder is to liberate the structural carriers, resulting in an increase of the diffusivity regardless of the defect trapping.

  6. 78 FR 66801 - Motor Carrier Safety Advisory Committee; Charter Renewal

    Science.gov (United States)

    2013-11-06

    ... DEPARTMENT OF TRANSPORTATION Federal Motor Carrier Safety Administration [Docket No. FMCSA-2006-26367] Motor Carrier Safety Advisory Committee; Charter Renewal AGENCY: Federal Motor Carrier Safety... and recommendations on motor carrier safety programs and motor carrier safety regulations through a...

  7. Understanding mobility degeneration mechanism in organic thin-film transistors (OTFT)

    Science.gov (United States)

    Wang, Wei; Wang, Long; Xu, Guangwei; Gao, Nan; Wang, Lingfei; Ji, Zhuoyu; Lu, Congyan; Lu, Nianduan; Li, Ling; Liu, Miwng

    2017-08-01

    Mobility degradation at high gate bias is often observed in organic thin film transistors. We propose a mechanism for this confusing phenomenon, based on the percolation theory with the presence of disordered energy landscape with an exponential density of states. Within a simple model we show how the surface states at insulator/organic interface trap a portion of channel carriers, and result in decrease of mobility as well as source/drain current with gate voltage. Depending on the competition between the carrier accumulation and surface trapping effect, two different carrier density dependences of mobility are obtained, in excellent agreement with experiment data.

  8. Charge carrier recombination dynamics in perovskite and polymer solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Paulke, Andreas; Kniepert, Juliane; Kurpiers, Jona; Wolff, Christian M.; Schön, Natalie; Brenner, Thomas J. K.; Neher, Dieter [Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24–25, 14476, Potsdam (Germany); Stranks, Samuel D. [Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Research Laboratory of Electronics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139 (United States); Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Snaith, Henry J. [Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom)

    2016-03-14

    Time-delayed collection field experiments are applied to planar organometal halide perovskite (CH{sub 3}NH{sub 3}PbI{sub 3}) based solar cells to investigate charge carrier recombination in a fully working solar cell at the nanosecond to microsecond time scale. Recombination of mobile (extractable) charges is shown to follow second-order recombination dynamics for all fluences and time scales tested. Most importantly, the bimolecular recombination coefficient is found to be time-dependent, with an initial value of ca. 10{sup −9} cm{sup 3}/s and a progressive reduction within the first tens of nanoseconds. Comparison to the prototypical organic bulk heterojunction device PTB7:PC{sub 71}BM yields important differences with regard to the mechanism and time scale of free carrier recombination.

  9. Hot carrier degradation in semiconductor devices

    CERN Document Server

    2015-01-01

    This book provides readers with a variety of tools to address the challenges posed by hot carrier degradation, one of today’s most complicated reliability issues in semiconductor devices.  Coverage includes an explanation of carrier transport within devices and book-keeping of how they acquire energy (“become hot”), interaction of an ensemble of colder and hotter carriers with defect precursors, which eventually leads to the creation of a defect, and a description of how these defects interact with the device, degrading its performance. • Describes the intricacies of hot carrier degradation in modern semiconductor technologies; • Covers the entire hot carrier degradation phenomenon, including topics such as characterization, carrier transport, carrier-defect interaction, technological impact, circuit impact, etc.; • Enables detailed understanding of carrier transport, interaction of the carrier ensemble with the defect precursors, and an accurate assessment of how the newly created defects imp...

  10. ISS qualified thermal carrier equipment

    Science.gov (United States)

    Deuser, Mark S.; Vellinger, John C.; Jennings, Wm. M.

    2000-01-01

    Biotechnology is undergoing a period of rapid and sustained growth, a trend which is expected to continue as the general population ages and as new medical treatments and products are conceived. As pharmaceutical and biomedical companies continue to search for improved methods of production and, for answers to basic research questions, they will seek out new avenues of research. Space processing on the International Space Station (ISS) offers such an opportunity! Space is rapidly becoming an industrial laboratory for biotechnology research and processing. Space bioprocessing offers exciting possibilities for developing new pharmaceuticals and medical treatments, which can be used to benefit mankind on Earth. It also represents a new economic frontier for the private sector. For over eight years, the thermal carrier development team at SHOT has been working with government and commercial sector scientists who are conducting microgravity experiments that require thermal control. SHOT realized several years ago that the hardware currently being used for microgravity thermal control was becoming obsolete. It is likely that the government, academic, and industrial bioscience community members could utilize SHOT's hardware as a replacement to their current microgravity thermal carrier equipment. Moreover, SHOT is aware of several international scientists interested in utilizing our space qualified thermal carrier. SHOT's economic financing concept could be extremely beneficial to the international participant, while providing a source of geographic return for their particular region. Beginning in 2000, flight qualified thermal carriers are expected to be available to both the private and government sectors. .

  11. Visualizing Carrier Transport in Metal Halide Perovskite Nanoplates via Electric Field Modulated Photoluminescence Imaging.

    Science.gov (United States)

    Hu, Xuelu; Wang, Xiao; Fan, Peng; Li, Yunyun; Zhang, Xuehong; Liu, Qingbo; Zheng, Weihao; Xu, Gengzhao; Wang, Xiaoxia; Zhu, Xiaoli; Pan, Anlian

    2018-05-09

    Metal halide perovskite nanostructures have recently been the focus of intense research due to their exceptional optoelectronic properties and potential applications in integrated photonics devices. Charge transport in perovskite nanostructure is a crucial process that defines efficiency of optoelectronic devices but still requires a deep understanding. Herein, we report the study of the charge transport, particularly the drift of minority carrier in both all-inorganic CsPbBr 3 and organic-inorganic hybrid CH 3 NH 3 PbBr 3 perovskite nanoplates by electric field modulated photoluminescence (PL) imaging. Bias voltage dependent elongated PL emission patterns were observed due to the carrier drift at external electric fields. By fitting the drift length as a function of electric field, we obtained the carrier mobility of about 28 cm 2 V -1 S -1 in the CsPbBr 3 perovskite nanoplate. The result is consistent with the spatially resolved PL dynamics measurement, confirming the feasibility of the method. Furthermore, the electric field modulated PL imaging is successfully applied to the study of temperature-dependent carrier mobility in CsPbBr 3 nanoplates. This work not only offers insights for the mobile carrier in metal halide perovskite nanostructures, which is essential for optimizing device design and performance prediction, but also provides a novel and simple method to investigate charge transport in many other optoelectronic materials.

  12. Mobile Marketing

    OpenAIRE

    竹安, 数博; Takeyasu, Kazuhiro

    2005-01-01

    This article deals with one of the modern trends in marketing communication, which is mobile marketing. Towards the end of 2008, several projects which use mobile phones for target marketing communication were launched. Commercial SMS´s are sent on the base of agreement or registration of the consumers on special websites, for example hellomobil.cz. The benefit for the consumers is the bonus which can have more forms - not only sending money to the account, free SMS´s/MMS´s and minutes but al...

  13. Mobile Usability

    DEFF Research Database (Denmark)

    Aryana, Bijan; Clemmensen, Torkil

    2013-01-01

    In this article, a country specific comparative mobile usability study is presented, using Iran and Turkey as the two chosen emerging/emergent nation exemplars of smartphone usage and adoption. In a focus group study, three mobile applications were selected by first-time users of smartphones...... personal contacts. The results and analysis establish the existence of country specific issues and concerns, as well as reveal generic usability issues. The article concludes that the source of these issues is most likely due to a combination of certain contextual features endemic to both Iran and Turkey...

  14. Hybrid Tunable Wideband Single Feed Antenna Element for Smartphones supporting Carrier Aggregation

    DEFF Research Database (Denmark)

    Stanev, Simon Peter; Tatomirescu, Alexandru

    2016-01-01

    This paper presents a single feed antenna with a dual branch matching circuit combined with a 3dB microstrip power divider to support the carrier aggregation in LTE advanced mobile handsets. By the use of the matching circuits, an independent and versatile broadband antenna is achieved. Hence, th...

  15. Ab initio theory of charge-carrier conduction in ultrapure organic crystals

    NARCIS (Netherlands)

    Hannewald, K.; Bobbert, P.A.

    2004-01-01

    We present an ab initio description of charge-carrier mobilities in organic molecular crystals of high purity. Our approach is based on Holstein's original concept of small-polaron bands but generalized with respect to the inclusion of nonlocal electron-phonon coupling. By means of an explicit

  16. Opportunistic tri-band carrier aggregation in licensed spectrum for multi-operator 5G hetnet

    Science.gov (United States)

    Maksymuk, Taras; Kyryk, Maryan; Klymash, Mykhailo; Jo, Minho; Romaniuk, Ryszard; Kotyra, Andrzej; Zhanpeisova, Aizhan; Kozbekova, Ainur

    2017-08-01

    Increasing capacity of mobile networks is a real challenge due to rapid increasing of traffic demands and spectrum scarcity. Carrier aggregation technology is aimed to increase the user data rate by combining the throughput of few spectrum bands, even if they are not physically collocated. Utilization of unlicensed Wi-Fi 5 GHz band for mobile transmission opens new perspectives for carrier aggregation due to vast amount of spectrum range, which can be available for aggregation to supplement data rates for end users. There are many solutions proposed to enable mobile data transmission in unlicensed band without disturbing interference for the existing Wi-Fi users. The paper presents a new approach for opportunistic carrier aggregation in licensed and unlicensed band for multi-operator 5G network. It allows multiple network operators to utilize unlicensed spectrum opportunistically if it is not currently used by Wi-Fi or other mobile network operators. Performance of the proposed approach has been simulated in case of two competing operators. Simulation results reveal that applying the proposed method ensures achieving satisfactory performance of carrier aggregation for the case of two network operators.

  17. Mobile cosmetics advisor: an imaging based mobile service

    Science.gov (United States)

    Bhatti, Nina; Baker, Harlyn; Chao, Hui; Clearwater, Scott; Harville, Mike; Jain, Jhilmil; Lyons, Nic; Marguier, Joanna; Schettino, John; Süsstrunk, Sabine

    2010-01-01

    Selecting cosmetics requires visual information and often benefits from the assessments of a cosmetics expert. In this paper we present a unique mobile imaging application that enables women to use their cell phones to get immediate expert advice when selecting personal cosmetic products. We derive the visual information from analysis of camera phone images, and provide the judgment of the cosmetics specialist through use of an expert system. The result is a new paradigm for mobile interactions-image-based information services exploiting the ubiquity of camera phones. The application is designed to work with any handset over any cellular carrier using commonly available MMS and SMS features. Targeted at the unsophisticated consumer, it must be quick and easy to use, not requiring download capabilities or preplanning. Thus, all application processing occurs in the back-end system and not on the handset itself. We present the imaging pipeline technology and a comparison of the services' accuracy with respect to human experts.

  18. Direct Effect of Dielectric Surface Energy on Carrier Transport in Organic Field-Effect Transistors.

    Science.gov (United States)

    Zhou, Shujun; Tang, Qingxin; Tian, Hongkun; Zhao, Xiaoli; Tong, Yanhong; Barlow, Stephen; Marder, Seth R; Liu, Yichun

    2018-05-09

    The understanding of the characteristics of gate dielectric that leads to optimized carrier transport remains controversial, and the conventional studies applied organic semiconductor thin films, which introduces the effect of dielectric on the growth of the deposited semiconductor thin films and hence only can explore the indirect effects. Here, we introduce pregrown organic single crystals to eliminate the indirect effect (semiconductor growth) in the conventional studies and to undertake an investigation of the direct effect of dielectric on carrier transport. It is shown that the matching of the polar and dispersive components of surface energy between semiconductor and dielectric is favorable for higher mobility. This new empirical finding may show the direct relationship between dielectric and carrier transport for the optimized mobility of organic field-effect transistors and hence show a promising potential for the development of next-generation high-performance organic electronic devices.

  19. Designing Mobilities

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    How is the width of the pavement shaping the urban experience? How is the material design of transport infrastructure and mobile technology affording social interaction in everyday life spaces? How do people inhabit these spaces with their bodies and in accordance to social and cultural norms...

  20. Mobile IP

    NARCIS (Netherlands)

    Heijenk, Geert; Sallent, S.; Pras, Aiko

    1999-01-01

    The Internet is growing exponentially, both in the amount of traffic carried, and in the amount of hosts connected. IP technology is becoming more and more important, in company networks (Intranets), and also in the core networks for the next generation mobile networks. Further, wireless access to

  1. Mobile Misfortune

    DEFF Research Database (Denmark)

    Vigh, Henrik Erdman

    2015-01-01

    of the mobility it enables. This article, thus, looks at the motives and manners in which young men in Bissau become caught up in transnational flows of cocaine. It shows how motion is emotively anchored and affectively bound: tied to and directed toward a feeling of worth and realisation of being, and how...

  2. Going Mobile?

    DEFF Research Database (Denmark)

    Tallon, Loic; Froes, Isabel Cristina G.

    2011-01-01

    If the future is mobile, how is the museum community developing within that future? What are the challenges museums face within it? In which directions should we be seeking to evolve our collective knowledge share? It was to gain observations on questions such as these that the 2011 Museums & Mob...

  3. Resource Mobilization

    International Development Research Centre (IDRC) Digital Library (Canada)

    Annex 1: The Scoping Study on Donor Funding for. Development Research in ... publication of the Resource Mobilization: A Practical Guide for Research .... applied the concept or technique, which validates the practical application of ... some other staff member would write up a grant application addressed to one, two, or a ...

  4. Mobile Phone

    Institute of Scientific and Technical Information of China (English)

    籍万杰

    2004-01-01

    Your mobile phone rings.and instead of usual electronic signals,it's playing your favorite music.A friend sends your favorite song to cheer you up.One day,a record company might forward new records and music videos to your phone.

  5. Electromigration of carrier-free radionuclides. 13

    International Nuclear Information System (INIS)

    Roesch, F.; Reimann, T.; Buglanov, G.V.; Milanov, M.; Khalkin, V.A.; Dreyer, R.

    1988-01-01

    Using a special type of on line electromigration measurements of γ-emitting radionuclides in homogeneous aqueous electrolytes free of supporting materials the electromigration behaviour of the carrier-free 241 Am-Am(III) in inert electrolytes, μ = 0.1 (ClO 4 - ), T = 298.1(1) K, was studied. Basing on experimental dependencies of the overall ion mobilities of 241 Am-Am(III) on pH between pH 5.5 and 12.9 the stoichiometric hydrolysis constants pβ 3 = 28.8(9) and pK 1 = 6.9(2) were obtained. For K 4 a limitation of pK 4 > 13.9(3) was possible, because no formation of anionic hydrolysis products in solutions pH 241 Am-Am(III) degrees in the range pH 5.5 - 3 from +6.85(15) up to +5.50(15) · 10 -4 cm 2 s -1 V -1 . Dependencies of this effect on overall ionic strength, inert electrolyte anion, and temperature of the electrolytes were studied in detail both in acidic and neutral solutions. (author)

  6. Capacity planning for Carrier Ethernet LTE backhaul networks

    DEFF Research Database (Denmark)

    Checko, Aleksandra; Ellegaard, Lars; Berger, Michael Stübert

    2012-01-01

    With the introduction of LTE networks operators need to plan a new, IP-based mobile backhaul. In this paper, we provide recommendation on dimensioning LTE backhaul networks links using three methods: delay-, dimensioning formula- and overbooking factor-based. Results are obtained from OPNET simul...... and verified. Simulation in this work proves that Carrier Ethernet, one of the candidate technologies for mobile backhaul, protects the network from users that want to flood the network with their data and manages to keep the delay experienced by other users low....... simulations with traffic model based on traffic forecast for 2015. A delay-based approach gives recommended bandwidth for expected number of users. A dimensioning formula is proposed to calculate link bandwidth when mean value of aggregated traffic in the network is known. An overbooking factor is calculated...

  7. Sensitivity of GRETINA position resolution to hole mobility

    Energy Technology Data Exchange (ETDEWEB)

    Prasher, V.S. [Department of Physics, University of Massachusetts Lowell, Lowell, MA 01854 (United States); Cromaz, M. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Merchan, E.; Chowdhury, P. [Department of Physics, University of Massachusetts Lowell, Lowell, MA 01854 (United States); Crawford, H.L. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Lister, C.J. [Department of Physics, University of Massachusetts Lowell, Lowell, MA 01854 (United States); Campbell, C.M.; Lee, I.Y.; Macchiavelli, A.O. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Radford, D.C. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Wiens, A. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2017-02-21

    The sensitivity of the position resolution of the gamma-ray tracking array GRETINA to the hole charge-carrier mobility parameter is investigated. The χ{sup 2} results from a fit of averaged signal (“superpulse”) data exhibit a shallow minimum for hole mobilities 15% lower than the currently adopted values. Calibration data on position resolution is analyzed, together with simulations that isolate the hole mobility dependence of signal decomposition from other effects such as electronics cross-talk. The results effectively exclude hole mobility as a dominant parameter for improving the position resolution for reconstruction of gamma-ray interaction points in GRETINA.

  8. Efficiency of some spectrochemical carriers

    International Nuclear Information System (INIS)

    Gomes, R.P.

    1978-01-01

    A comparative study of the efficiency of some spectrochemical carriers for the quantitative spectrographic analysis of Ag, Al, B, Bi, Cd, Cr, Cu, Fe, Mg, Mn, Mo, Ni, P, Pb, Si, Sn, V and Zn in uranium-base materials is presented. The volatility behavior of the eighteen elements is verified by means of the moving plate technique and each of the mentioned carriers. The best results are obtained with 4% In 2 O 3 , 6% AgCl and 5% NaF in a U 3 O 8 matrix. The sensitivities for some elements were extended to fractions of p.p.m. The precision, accuracy and acceptability of the method are calculated for all elements. The total error values as approximately in the range of 16-45% [pt

  9. Preventative maintenance of straddle carriers

    Directory of Open Access Journals (Sweden)

    Si Li

    2015-04-01

    Objectives: The purpose of this industry-driven study is to model preventative maintenance (PM influences on the operational effectiveness of straddle carriers. Method: The study employs historical data consisting of 21 273 work orders covering a 27-month period. Two models are developed, both of which forecast influences of PM regimes for different types of carrier. Results: The findings of the study suggest that the reliability of the straddle fleet decreases with increased intervals of PM services. The study also finds that three factors – namely resources, number of new straddles, and the number of new lifting work centres – influence the performances of straddles. Conclusion: The authors argue that this collaborative research exercise makes a significant contribution to existing supply chain management literature, particularly in the area of operations efficiency. The study also serves as an avenue to enhance relevant management practice.

  10. High electron mobility and large magnetoresistance in the half-Heusler semimetal LuPtBi

    KAUST Repository

    Hou, Zhipeng; Wang, Wenhong; Xu, Guizhou; Zhang, Xiaoming; Wei, Zhiyang; Shen, Shipeng; Liu, Enke; Yao, Yuan; Chai, Yisheng; Sun, Young; Xi, Xuekui; Wang, Wenquan; Liu, Zhongyuan; Wu, Guangheng; Zhang, Xixiang

    2015-01-01

    Materials with high carrier mobility showing large magnetoresistance (MR) have recently received much attention because of potential applications in future high-performance magnetoelectric devices. Here, we report on an electron-hole

  11. Mobile Customer Relationship Management and Mobile Security

    Science.gov (United States)

    Sanayei, Ali; Mirzaei, Abas

    The purpose of this study is twofold. First, in order to guarantee a coherent discussion about mobile customer relationship management (mCRM), this paper presents a conceptualization of mCRM delineating its unique characteristics because of Among the variety of mobile services, considerable attention has been devoted to mobile marketing and in particular to mobile customer relationship management services. Second, the authors discusses the security risks in mobile computing in different level(user, mobile device, wireless network,...) and finally we focus on enterprise mobile security and it's subgroups with a series of suggestion and solution for improve mobile computing security.

  12. Protein carriers of conjugate vaccines

    Science.gov (United States)

    Pichichero, Michael E

    2013-01-01

    The immunogenicity of polysaccharides as human vaccines was enhanced by coupling to protein carriers. Conjugation transformed the T cell-independent polysaccharide vaccines of the past to T cell-dependent antigenic vaccines that were much more immunogenic and launched a renaissance in vaccinology. This review discusses the conjugate vaccines for prevention of infections caused by Hemophilus influenzae type b, Streptococcus pneumoniae, and Neisseria meningitidis. Specifically, the characteristics of the proteins used in the construction of the vaccines including CRM, tetanus toxoid, diphtheria toxoid, Neisseria meningitidis outer membrane complex, and Hemophilus influenzae protein D are discussed. The studies that established differences among and key features of conjugate vaccines including immunologic memory induction, reduction of nasopharyngeal colonization and herd immunity, and antibody avidity and avidity maturation are presented. Studies of dose, schedule, response to boosters, of single protein carriers with single and multiple polysaccharides, of multiple protein carriers with multiple polysaccharides and conjugate vaccines administered concurrently with other vaccines are discussed along with undesirable consequences of conjugate vaccines. The clear benefits of conjugate vaccines in improving the protective responses of the immature immune systems of young infants and the senescent immune systems of the elderly have been made clear and opened the way to development of additional vaccines using this technology for future vaccine products. PMID:23955057

  13. 7 CFR 33.4 - Carrier.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Carrier. 33.4 Section 33.4 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... ISSUED UNDER AUTHORITY OF THE EXPORT APPLE ACT Definitions § 33.4 Carrier. Carrier means any common or...

  14. 8 CFR 217.6 - Carrier agreements.

    Science.gov (United States)

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Carrier agreements. 217.6 Section 217.6 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS VISA WAIVER PROGRAM § 217... may notify a carrier of the existence of a basis for termination of a carrier agreement under this...

  15. 14 CFR 271.4 - Carrier costs.

    Science.gov (United States)

    2010-01-01

    ... Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS GUIDELINES FOR SUBSIDIZING AIR CARRIERS PROVIDING ESSENTIAL AIR TRANSPORTATION § 271.4 Carrier costs. (a) The reasonable costs projected for a carrier providing essential air service at an eligible...

  16. 14 CFR 271.5 - Carrier revenues.

    Science.gov (United States)

    2010-01-01

    ... Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS GUIDELINES FOR SUBSIDIZING AIR CARRIERS PROVIDING ESSENTIAL AIR TRANSPORTATION § 271.5 Carrier revenues. (a) The projected passenger revenue for a carrier providing essential air service at an eligible...

  17. The African Mobile Story

    DEFF Research Database (Denmark)

    This book identifies the factors that has enabled the growth of mobile telephony in Africa. The book covers the regulatory factors, the development and usage of mobile application, mobile security and sustainable power source for mobile networks...

  18. 14 CFR 399.82 - Passing off of carrier identity by affiliation between carriers.

    Science.gov (United States)

    2010-01-01

    ... forth in paragraph (c) of this section. In such cases the Board may determine in an adjudicatory... carrier shall not engage in joint public relations activities at points served by both carriers which tend... either carrier are performed in common with the other carrier or as part of a single system. In cases...

  19. Pore-Confined Carriers and Biomolecules in Mesoporous Silica for Biomimetic Separation and Targeting

    Science.gov (United States)

    Zhou, Shanshan

    Selectively permeable biological membranes composed of lipophilic barriers inspire the design of biomimetic carrier-mediated membranes for aqueous solute separation. This work imparts selective permeability to lipid-filled pores of silica thin film composite membranes using carrier molecules that reside in the lipophilic self-assemblies. The lipids confined inside the pores of silica are proven to be a more effective barrier than bilayers formed on the porous surface through vesicle fusion, which is critical for quantifying the function of an immobilized carrier. The ability of a lipophilic carrier embedded in the lipid bilayer to reversibly bind the target solute and transport it through the membrane is demonstrated. Through the functionalization of the silica surface with enzymes, enzymatic catalysis and biomimetic separations can be combined on this nanostructured composite platform. The successful development of biomimetic nanocomposite membrane can provide for efficient dilute aqueous solute upgrading or separations using engineered carrier/catalyst/support systems. While the carrier-mediated biomimetic membranes hold great potential, fully understanding of the transport processes in composite synthetic membranes is essential for improve the membrane performance. Electrochemical impedance spectroscopy (EIS) technique is demonstrated to be a useful tool for characterizing the thin film pore accessibility. Furthermore, the effect of lipid bilayer preparation methods on the silica thin film (in the form of pore enveloping, pore filling) on ion transport is explored, as a lipid bilayer with high electrically insulation is essential for detecting activity of proteins or biomimetic carriers in the bilayer. This study provides insights for making better barriers on mesoporous support for carrier-mediated membrane separation process. Porous silica nanoparticles (pSNPs) with pore sizes appropriate for biomolecule loading are potential for encapsulating dsRNA within the

  20. Mobile weatherstation

    International Nuclear Information System (INIS)

    Hahn, H.; Koutny, P.; Schwabach, H.; Eisenwagner, H.

    1981-01-01

    A mobile weatherstation is described which allows to measure the following parameters: airtemperature, relative humidity, winddirection and windspeed. The station consists of three main units: the central station METEODAT, the multiplexer and the weather measure tower with the sensors. The measured data are displayed in digital form in the central unit and can be printed on a teletype. The power supply is either 220 Volt AC or 24 Volt DC. (author)

  1. SC-FDMA for mobile communications

    CERN Document Server

    Abd El-Samie, Fathi E

    2013-01-01

    SC-FDMA for Mobile Communications examines Single-Carrier Frequency Division Multiple Access (SC-FDMA). Explaining this rapidly evolving system for mobile communications, it describes its advantages and limitations and outlines possible solutions for addressing its current limitations. The book explores the emerging trend of cooperative communication with SC-FDMA and how it can improve the physical layer security. It considers the design of distributed coding schemes and protocols for wireless relay networks where users cooperate to send their data to the destination. Supplying you with the re

  2. Structural Mobility, Exchange Mobility and Subgroup Consistent Mobility Measurement – US–German Mobility Measurements Revisited

    OpenAIRE

    C. SCHLUTER; D. VAN DE GAER

    2008-01-01

    We formalize the concept of structural mobility and use the framework of subgroup consistent mobility measurement to derive a relative and an absolute measure of mobility that is increasing both in upward structural mobility and exchange mobility. In our empirical illustration, we contribute substantively to the ongoing debate about mobility rankings between the USA and Germany.

  3. The simulation of pulsed heater for a sampling system for the ion mobility spectrometer

    International Nuclear Information System (INIS)

    Malkin, Evgeniy

    2011-01-01

    The development of the sampling device with pulsed heating of the intermediate carrier for ion mobility spectrometer is described in this article. Numerical simulation of a pulse heater structure of is presented. The design of the sampling device using a pulsed heating of the intermediate carrier is developed. Experimental results of approval of the sampling device are presented.

  4. Non-permeable substrate carrier for electroplating

    Science.gov (United States)

    Abas, Emmanuel Chua; Chen, Chen-An; Ma, Diana Xiaobing; Ganti, Kalyana Bhargava

    2012-11-27

    One embodiment relates to a substrate carrier for use in electroplating a plurality of substrates. The substrate carrier comprises a non-conductive carrier body on which the substrates are to be held. Electrically-conductive lines are embedded within the carrier body, and a plurality of contact clips are coupled to the electrically-conductive lines embedded within the carrier body. The contact clips hold the substrates in place and electrically couple the substrates to the electrically-conductive lines. The non-conductive carrier body is continuous so as to be impermeable to flow of electroplating solution through the non-conductive carrier body. Other embodiments, aspects and features are also disclosed.

  5. 47 CFR 25.143 - Licensing provisions for the 1.6/2.4 GHz mobile-satellite service and 2 GHz mobile-satellite...

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Licensing provisions for the 1.6/2.4 GHz mobile-satellite service and 2 GHz mobile-satellite service. 25.143 Section 25.143 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses...

  6. Polaron mobility obtained by a variational approach for lattice Fröhlich models

    Science.gov (United States)

    Kornjača, Milan; Vukmirović, Nenad

    2018-04-01

    Charge carrier mobility for a class of lattice models with long-range electron-phonon interaction was investigated. The approach for mobility calculation is based on a suitably chosen unitary transformation of the model Hamiltonian which transforms it into the form where the remaining interaction part can be treated as a perturbation. Relevant spectral functions were then obtained using Matsubara Green's functions technique and charge carrier mobility was evaluated using Kubo's linear response formula. Numerical results were presented for a wide range of electron-phonon interaction strengths and temperatures in the case of one-dimensional version of the model. The results indicate that the mobility decreases with increasing temperature for all electron-phonon interaction strengths in the investigated range, while longer interaction range leads to more mobile carriers.

  7. Mobile Termination and Mobile Penetration

    OpenAIRE

    Hurkens, Sjaak; Jeon, Doh-Shin

    2009-01-01

    In this paper, we study how access pricing affects network competition when subscription demand is elastic and each network uses non-linear prices and can apply termination-based price discrimination. In the case of a fixed per minute termination charge, we find that a reduction of the termination charge below cost has two oppos- ing effects: it softens competition but helps to internalize network externalities. The former reduces mobile penetration while the latter boosts it. We find that fi...

  8. Mobile termination and mobile penetration

    OpenAIRE

    Hurkens, Sjaak

    2009-01-01

    In this paper, we study how access pricing affects network competition when subscription demand is elastic and each network uses non-linear prices and can apply termination-based price discrimination. In the case of a fixed per minute termination charge, we find that a reduction of the termination charge below cost has two opposing effects: it softens competition but helps to internalize network externalities. The former reduces mobile penetration while the latter boosts it. We find that firm...

  9. 76 FR 32390 - Motor Carrier Safety Advisory Committee Public Meeting

    Science.gov (United States)

    2011-06-06

    ... DEPARTMENT OF TRANSPORTATION Federal Motor Carrier Safety Administration [Docket No. FMCSA-2006-26367] Motor Carrier Safety Advisory Committee Public Meeting AGENCY: Federal Motor Carrier Safety Administration (FMCSA), DOT. ACTION: Notice of Motor Carrier Safety Advisory Committee (MCSAC) Meeting. SUMMARY...

  10. 77 FR 46555 - Motor Carrier Safety Advisory Committee: Public Meeting

    Science.gov (United States)

    2012-08-03

    ... DEPARTMENT OF TRANSPORTATION Federal Motor Carrier Safety Administration [Docket No. FMCSA-2006-26367] Motor Carrier Safety Advisory Committee: Public Meeting AGENCY: Federal Motor Carrier Safety Administration (FMCSA), DOT. ACTION: Notice of meeting of Motor Carrier Safety Advisory Committee (MCSAC...

  11. 75 FR 2923 - Motor Carrier Safety Advisory Committee Public Meeting

    Science.gov (United States)

    2010-01-19

    ... DEPARTMENT OF TRANSPORTATION Federal Motor Carrier Safety Administration [Docket No. FMCSA-2006-26367] Motor Carrier Safety Advisory Committee Public Meeting AGENCY: Federal Motor Carrier Safety Administration (FMCSA), DOT. ACTION: Notice of Motor Carrier Safety Advisory Committee Meeting. SUMMARY: FMCSA...

  12. 75 FR 29384 - Motor Carrier Safety Advisory Committee Public Meeting

    Science.gov (United States)

    2010-05-25

    ... DEPARTMENT OF TRANSPORTATION Federal Motor Carrier Safety Administration [Docket No. FMCSA-2010-0143] Motor Carrier Safety Advisory Committee Public Meeting AGENCY: Federal Motor Carrier Safety Administration (FMCSA), DOT. ACTION: Notice of Motor Carrier Safety Advisory Committee meeting. SUMMARY: FMCSA...

  13. 75 FR 72863 - Motor Carrier Safety Advisory Committee Public Meeting

    Science.gov (United States)

    2010-11-26

    ... DEPARTMENT OF TRANSPORTATION Federal Motor Carrier Safety Administration [Docket No. FMCSA-2006-26367] Motor Carrier Safety Advisory Committee Public Meeting AGENCY: Federal Motor Carrier Safety Administration, DOT. ACTION: Notice of Motor Carrier Safety Advisory Committee Meeting. SUMMARY: FMCSA announces...

  14. 75 FR 50797 - Motor Carrier Safety Advisory Committee Public Meeting

    Science.gov (United States)

    2010-08-17

    ... DEPARTMENT OF TRANSPORTATION Federal Motor Carrier Safety Administration [Docket No. FMCSA-2010-0143] Motor Carrier Safety Advisory Committee Public Meeting AGENCY: Federal Motor Carrier Safety Administration (FMCSA), DOT. ACTION: Notice of Motor Carrier Safety Advisory Committee Meeting. SUMMARY: FMCSA...

  15. Mobile Payments : Comparison of Mobile Wallet Concepts

    OpenAIRE

    Narayan, Srikant

    2013-01-01

    Mobile payments are an emerging trend and an alternative to traditional payment methods. Mobile payments involve the usage of the mobile phone to handle credit transfers during purchase of goods and peer to peer money transfers referred to as mobile wallet service, instead of depending on bank cards and cash. In this scenario, while the mobile wallet industry still being in its infancy there exist a few drivers of mobile wallet solutions aiming to create a de-facto standard in the mobile mark...

  16. Carrier transport and electronic structure in amorphous oxide semiconductor, a-InGaZnO4

    International Nuclear Information System (INIS)

    Takagi, Akihiro; Nomura, Kenji; Ohta, Hiromichi; Yanagi, Hiroshi; Kamiya, Toshio; Hirano, Masahiro; Hosono, Hideo

    2005-01-01

    Carrier transport properties in amorphous oxide semiconductor InGaZnO 4 (a-IGZO) thin films were investigated in detail using temperature dependence of Hall measurements. It was found that Hall mobility increased distinctly as carrier concentration increased. Unlikely conventional amorphous semiconductors such as a-Si/H, definite normal Hall voltage signals were observed on the films with carrier concentrations (N e )>10 16 cm -3 , and Hall mobilities as large as 15 cm 2 (Vs) -1 were attained in the films with N e >10 20 cm -3 . When N e was less than 10 19 cm -3 , the temperature dependence of Hall mobility showed thermally-activated behavior in spite that carrier concentration was independent of temperature. While, it changed to almost degenerate conduction at N e >10 18 cm -3 . These behaviors are similar to those observed in single-crystalline IGZO, and are explained by percolation conduction through distributed potential barriers which are formed in the vicinity of the conduction band bottom due to the randomness of the amorphous structure. The effective mass of a-IGZO was estimated to be ∼0.34 m e (m e is the mass of free electron) from optical data, which is almost the same as that of crystalline IGZO (∼0.32 m e )

  17. Wuestite - a solar energy carrier

    Energy Technology Data Exchange (ETDEWEB)

    Weidenkaff, A; Nueesch, P; Wokaun, A [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Reller, A [Hamburg Univ., Hamburg (Germany)

    1997-06-01

    Hydrogen is produced when Wuestite (Fe{sub 1-y}O) is oxidised by water. This reaction is part of a two-step thermochemical metal oxide cycle for the storage of solar energy in the form of chemical energy carriers, characterised by a high chemical potential. The reaction was studied in a tubular furnace with on-line gas analysis and further characterised in detail by DTA und high-temperature X-ray powder diffraction. The influence of non-stoichiometry, morphology and temperature on the mechanism and kinetics of the water-splitting reaction was determined. (author) 3 figs., tabs., 3 refs.

  18. Biocheese: A Food Probiotic Carrier

    Science.gov (United States)

    Castro, J. M.; Tornadijo, M. E.; Fresno, J. M.; Sandoval, H.

    2015-01-01

    This review describes some aspects related to the technological barriers encountered in the development and stability of probiotic cheeses. Aspects concerning the viability of probiotic cultures in this matrix are discussed and the potential of cheese as a biofunctional food carrier is analyzed, outlying some points related to health and safety. In general, the manufacture of probiotic cheese should have little change when compared with the elaboration of cheese in the traditional way. The physicochemical and technological parameters influencing the quality of these products have also to be measured so as to obtain a process optimization. PMID:25802862

  19. Vectorization of agrochemicals: amino acid carriers are more efficient than sugar carriers to translocate phenylpyrrole conjugates in the Ricinus system.

    Science.gov (United States)

    Wu, Hanxiang; Marhadour, Sophie; Lei, Zhi-Wei; Yang, Wen; Marivingt-Mounir, Cécile; Bonnemain, Jean-Louis; Chollet, Jean-François

    2018-05-01

    Producing quality food in sufficient quantity while using less agrochemical inputs will be one of the great challenges of the twenty-first century. One way of achieving this goal is to greatly reduce the doses of plant protection compounds by improving the targeting of pests to eradicate. Therefore, we developed a vectorization strategy to confer phloem mobility to fenpiclonil, a contact fungicide from the phenylpyrrole family used as a model molecule. It consists in coupling the antifungal compound to an amino acid or a sugar, so that the resulting conjugates are handled by active nutrient transport systems. The method of click chemistry was used to synthesize three conjugates combining fenpiclonil to glucose or glutamic acid with a spacer containing a triazole ring. Systemicity tests with the Ricinus model have shown that the amino acid promoiety was clearly more favorable to phloem mobility than that of glucose. In addition, the transport of the amino acid conjugate is carrier mediated since the derivative of the L series was about five times more concentrated in the phloem sap than its counterpart of the D series. The systemicity of the L-derivative is pH dependent and almost completely inhibited by the protonophore carbonyl cyanide 3-chlorophenylhydrazone (CCCP). These data suggest that the phloem transport of the L-derivative is governed by a stereospecific amino acid carrier system energized by the proton motive force.

  20. Mobile Marketing

    OpenAIRE

    Luengo Cascudo, Alberto

    2010-01-01

    El principal objetivo de este proyecto es explicar y entender la importancia del Mobile Marketing como nueva herramienta de negocio en el Marketing empresarial. Para ello, el primer objetivo es entender los dos factores que para mí son la clave de su importancia: la evolución del entorno tecnológico y el cambio en los hábitos del consumidor. Debido a la novedad de esta nueva forma de Marketing y al hecho de que está en constante definición, es básico exponer de la forma más cla...

  1. Wapice News Mobile Application

    OpenAIRE

    Söylemez, Ilke

    2017-01-01

    Since the mobile phones started to have an increasingly significant role in daily life, the mobile application development also started to be an important area in the software industry. The problem for mobile application developers is to develop a mobile application which supports all the devices and platforms on the market. This issue created a need for cross platform mobile applications. The cross platform mobile development refers to the development of mobile applications that could be use...

  2. Silicon nanowire hot carrier electroluminescence

    Energy Technology Data Exchange (ETDEWEB)

    Plessis, M. du, E-mail: monuko@up.ac.za; Joubert, T.-H.

    2016-08-31

    Avalanche electroluminescence from silicon pn junctions has been known for many years. However, the internal quantum efficiencies of these devices are quite low due to the indirect band gap nature of the semiconductor material. In this study we have used reach-through biasing and SOI (silicon-on-insulator) thin film structures to improve the internal power efficiency and the external light extraction efficiency. Both continuous silicon thin film pn junctions and parallel nanowire pn junctions were manufactured using a custom SOI technology. The pn junctions are operated in the reach-through mode of operation, thus increasing the average electric field within the fully depleted region. Experimental results of the emission spectrum indicate that the most dominant photon generating mechanism is due to intraband hot carrier relaxation processes. It was found that the SOI nanowire light source external power efficiency is at least an order of magnitude better than the comparable bulk CMOS (Complementary Metal Oxide Semiconductor) light source. - Highlights: • We investigate effect of electric field on silicon avalanche electroluminescence. • With reach-through pn junctions the current and carrier densities are kept constant. • Higher electric fields increase short wavelength radiation. • Higher electric fields decrease long wavelength radiation. • The effect of the electric field indicates intraband transitions as main mechanism.

  3. Understanding the Representativeness of Mobile Phone Location Data in Characterizing Human Mobility Indicators

    Directory of Open Access Journals (Sweden)

    Shiwei Lu

    2017-01-01

    Full Text Available The advent of big data has aided understanding of the driving forces of human mobility, which is beneficial for many fields, such as mobility prediction, urban planning, and traffic management. However, the data sources used in many studies, such as mobile phone location and geo-tagged social media data, are sparsely sampled in the temporal scale. An individual’s records can be distributed over a few hours a day, or a week, or over just a few hours a month. Thus, the representativeness of sparse mobile phone location data in characterizing human mobility requires analysis before using data to derive human mobility patterns. This paper investigates this important issue through an approach that uses subscriber mobile phone location data collected by a major carrier in Shenzhen, China. A dataset of over 5 million mobile phone subscribers that covers 24 h a day is used as a benchmark to test the representativeness of mobile phone location data on human mobility indicators, such as total travel distance, movement entropy, and radius of gyration. This study divides this dataset by hour, using 2- to 23-h segments to evaluate the representativeness due to the availability of mobile phone location data. The results show that different numbers of hourly segments affect estimations of human mobility indicators and can cause overestimations or underestimations from the individual perspective. On average, the total travel distance and movement entropy tend to be underestimated. The underestimation coefficient results for estimation of total travel distance are approximately linear, declining as the number of time segments increases, and the underestimation coefficient results for estimating movement entropy decline logarithmically as the time segments increase, whereas the radius of gyration tends to be more ambiguous due to the loss of isolated locations. This paper suggests that researchers should carefully interpret results derived from this type of

  4. Charge carrier motion in disordered conjugated polymers: a multiscale ab-initio study

    Energy Technology Data Exchange (ETDEWEB)

    Vukmirovic, Nenad; Wang, Lin-Wang

    2009-11-10

    We developed an ab-initio multiscale method for simulation of carrier transport in large disordered systems, based on direct calculation of electronic states and electron-phonon coupling constants. It enabled us to obtain the never seen before rich microscopic details of carrier motion in conjugated polymers, which led us to question several assumptions of phenomenological models, widely used in such systems. The macroscopic mobility of disordered poly(3- hexylthiophene) (P3HT) polymer, extracted from our simulation, is in agreement with experimental results from the literature.

  5. Efficient photogeneration of charge carriers in silicon nanowires with a radial doping gradient

    International Nuclear Information System (INIS)

    Murthy, D H K; Houtepen, A J; Savenije, T J; Siebbeles, L D A; Xu, T; Nys, J P; Krzeminski, C; Grandidier, B; Stievenard, D; Chen, W H; Pareige, P; Jomard, F; Patriarche, G; Lebedev, O I

    2011-01-01

    by performing electrodeless time-resolved microwave conductivity measurements, the efficiency of charge carrier generation, their mobility, and the decay kinetics on photoexcitation were studied in arrays of Si nanowires grown by the vapor-liquid-solid mechanism. Large enhancements in the magnitude of the photoconductance and charge carrier lifetime are found depending on the incorporation of impurities during the growth. They are explained by the internal electric field that builds up, due to higher doped sidewalls, as revealed by detailed analysis of the nanowire morphology and chemical composition.

  6. Low-complexity Joint Sub-carrier Phase Noise Compensation for Digital Multi-carrier Systems

    DEFF Research Database (Denmark)

    Yankov, Metodi Plamenov; Barletta, Luca; Zibar, Darko

    2017-01-01

    Joint sub-carrier phase noise processing is proposed which recovers the SNR penalty related to decreased sub-carrier baudrate w.r.t. single carrier systems. The method enables digital sub-banding to be safely employed for nonlinear mitigation for modulation formats of up to 256-QAM.......Joint sub-carrier phase noise processing is proposed which recovers the SNR penalty related to decreased sub-carrier baudrate w.r.t. single carrier systems. The method enables digital sub-banding to be safely employed for nonlinear mitigation for modulation formats of up to 256-QAM....

  7. Differential Analysis of the Nasal Microbiome of Pig Carriers or Non-Carriers of Staphylococcus aureus

    DEFF Research Database (Denmark)

    Espinosa-Gongora, Carmen; Larsen, Niels; Schonning, Kristian

    2016-01-01

    pathogen in animal carriers. The aim of this study was to determine whether the nasal microbiome of pig S. aureus carriers differs from that of non-carriers. The V3-V5 region of the 16S rRNA gene was sequenced from nasal swabs of 44 S. aureus carriers and 56 non-carriers using the 454 GS FLX titanium...... microbiome of pigs that are not colonized with S. aureus harbours several species/taxa that are significantly less abundant in pig carriers, suggesting that the nasal microbiota may play a role in the individual predisposition to S. aureus nasal carriage in pigs. Further research is warranted to isolate...

  8. Inert carriers for column extraction chromatography

    International Nuclear Information System (INIS)

    Katykhin, G.S.

    1978-01-01

    Inert carriers used in column extraction chromatography are reviewed. Such carriers are devided into two large groups: hydrophilic carriers which possess high surface energy and are well wetted only with strongly polar liquids (kieselguhrs, silica gels, glasses, cellulose, Al 2 O 3 ) and water-repellent carriers which possess low surface energy and are well wetted with various organic solvents (polyethylene, polytetrafluorethylene polytrifluorochlorethylene). Properties of various carriers are presented: structure, chemical and radiation stability, adsorption properties, extracting agent capacity. The effect of structure and sizes of particles on the efficiency of chromatography columns is considered. Ways of immovable phase deposition on the carrier and the latter's regeneration. Peculiarities of column packing for preparative and continuous chromatography are discussed

  9. Temperature dependence of ballistic mobility in a metamorphic InGaAs/InAlAs high electron mobility transistor

    International Nuclear Information System (INIS)

    Lee, Jongkyong; Gang, Suhyun; Jo, Yongcheol; Kim, Jongmin; Woo, Hyeonseok; Han, Jaeseok; Kim, Hyungsang; Im, Hyunsik

    2014-01-01

    We have investigated the temperature dependence of ballistic mobility in a 100 nm-long InGaAs/InAlAs metamorphic high-electron-mobility transistor designed for millimeter-wavelength RF applications. To extract the temperature dependence of quasi-ballistic mobility, our experiment involves measurements of the effective mobility in the low-bias linear region of the transistor and of the collision-dominated Hall mobility using a gated Hall bar of the same epitaxial structure. The data measured from the experiment are consistent with that of modeled ballistic mobility based on ballistic transport theory. These results advance the understanding of ballistic transport in various transistors with a nano-scale channel length that is comparable to the carrier's mean free path in the channel.

  10. Advertising on mobile applications

    OpenAIRE

    Sobolevsky, Alexandr

    2015-01-01

    The article analyzes the new method of mobile advertising. Advertising in mobile applications - a subspecies of mobile marketing, where advertising is distributed using mobile phones and smartphones. Ad placement is going on inside of applications and games for smartphones. It has a high potential due to the large number of mobile phone users (over 6.5 billion in 2013).

  11. Mobility Balance Sheet 2009

    International Nuclear Information System (INIS)

    Jorritsma, P.; Derriks, H.; Francke, J.; Gordijn, H.; Groot, W.; Harms, L.; Van der Loop, H.; Peer, S.; Savelberg, F.; Wouters, P.

    2009-06-01

    The Mobility Balance Sheet provides an overview of the state of the art of mobility in the Netherlands. In addition to describing the development of mobility this report also provides explanations for the growth of passenger and freight transport. Moreover, the Mobility Balance Sheet also focuses on a topical theme: the effects of economic crises on mobility. [nl

  12. Aerial Logistics Management for Carrier Onboard Delivery

    Science.gov (United States)

    2016-09-01

    NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS AERIAL LOGISTICS MANAGEMENT FOR CARRIER ONBOARD DELIVERY by Samuel L. Chen September 2016...AND SUBTITLE AERIAL LOGISTICS MANAGEMENT FOR CARRIER ONBOARD DELIVERY 5. FUNDING NUMBERS 6. AUTHOR(S) Samuel L. Chen 7. PERFORMING ORGANIZATION NAME(S...delivery (COD) is the use of aircraft to transport people and cargo from a forward logistics site (FLS) to a carrier strike group (CSG). The goal of

  13. Mobile video with mobile IPv6

    CERN Document Server

    Minoli, Daniel

    2012-01-01

    Increased reliance on mobile devices and streaming of video content are two of the most recent changes that have led those in the video distribution industry to be concerned about the shifting or erosion of traditional advertising revenues. Infrastructure providers also need to position themselves to take advantage of these trends. Mobile Video with Mobile IPv6provides an overview of the current mobile landscape, then delves specifically into the capabilities and operational details of IPv6. The book also addresses 3G and 4G services, the application of Mobile IPv6 to streaming and other mobil

  14. Both Hemophilia Health Care Providers and Hemophilia A Carriers Report that Carriers have Excessive Bleeding

    Science.gov (United States)

    Paroskie, Allison; Oso, Olatunde; DeBaun, Michael R.; Sidonio, Robert F

    2014-01-01

    Introduction Hemophilia A, the result of reduced factor VIII (FVIII) activity, is an X-linked recessive bleeding disorder. Previous reports of Hemophilia A carriers suggest an increased bleeding tendency. Our objective was to determine the attitudes and understanding of the Hemophilia A carrier bleeding phenotype, and opinions regarding timing of carrier testing from the perspective of both medical providers and affected patients. Data from this survey was used as preliminary data for an ongoing prospective study. Material and Methods An electronic survey was distributed to physicians and nurses employed at Hemophilia Treatment Centers (HTC), and Hemophilia A carriers who were members of Hemophilia Federation of America. Questions focused on the clinical understanding of bleeding symptoms and management of Hemophilia A carriers, and the timing and intensity of carrier testing. Results Our survey indicates that 51% (36/51) of providers compared to 78% (36/46) of carriers believe that Hemophilia A carriers with normal FVIII activity have an increased bleeding tendency (pHemophilia A carriers report a high frequency of bleeding symptoms. Regarding carrier testing, 72% (50/69) of medical providers recommend testing after 14 years of age, conversely 65% (29/45) of Hemophilia A carriers prefer testing to be done prior to this age (pHemophilia A carriers self-report a higher frequency of bleeding than previously acknowledged, and have a preference for earlier testing to confirm carrier status. PMID:24309601

  15. Micro-structure-mobility correlation in self-organised, conjugated polymer field-effect transistors

    NARCIS (Netherlands)

    Sirringhaus, H.; Brown, P.J.; Friend, R.H.; Nielsen, M.M.; Bechgaard, K.; Langeveld-Voss, B.M.W.; Spiering, A.J.H.; Janssen, R.A.J.; Meijer, E.W.

    2000-01-01

    We have investigated the correlation between polymer microstructure and charge carrier mobility in high-mobility, self-organised field-effect transistors of poly-3-hexyl-thiophene (P3HT). Two different preferential orientations of the microcrystalline P3HT domains with respect to the substrate have

  16. Temperature dependence of mobility in silicon (100) inversion layers at low temperatures

    International Nuclear Information System (INIS)

    Kawaguchi, Y.; Suzuki, T.; Kawaji, S.

    1982-01-01

    Electron mobility of Si(100) n-inversion layers in MOSFETs having μsub(peak) (4.2 K) = 4000.6500 and 12000 cm 2 /V x s has been measured at temperatures between 1 and 80 K. The carrier concentration dependence of the mobility extrapolated to T = O and the temperature dependent part of the scattering probability are investigated. (orig.)

  17. The design of a linear L-band high power amplifier for mobile communication satellites

    Science.gov (United States)

    Whittaker, N.; Brassard, G.; Li, E.; Goux, P.

    1990-01-01

    A linear L-band solid state high power amplifier designed for the space segment of the Mobile Satellite (MSAT) mobile communication system is described. The amplifier is capable of producing 35 watts of RF power with multitone signal at an efficiency of 25 percent and with intermodulation products better than 16 dB below carrier.

  18. Microstructure-mobility correlation in self-organised, conjugated polymer field-effect transistors

    DEFF Research Database (Denmark)

    Sirringhaus, H.; Brown, P.J.; Friend, R.H.

    2000-01-01

    We have investigated the correlation between polymer microstructure and charge carrier mobility in high-mobility, self-organised field-effect transistors of poly-3-hexyl-thiophene (P3HT). Two different preferential orientations of the microcrystalline P3HT domains with respect to the substrate have...

  19. Impact of energy filtering and carrier localization on the thermoelectric properties of granular semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Narducci, Dario, E-mail: dario.narducci@unimib.it [Department of Materials Science, University of Milano Bicocca, via Cozzi 53, 20125 Milano (Italy); Consorzio DeltaTi Research (Italy); Selezneva, Ekaterina [Department of Materials Science, University of Milano Bicocca, via Cozzi 53, 20125 Milano (Italy); Cerofolini, Gianfranco [Department of Materials Science, University of Milano Bicocca, via Cozzi 53, 20125 Milano (Italy); Consorzio DeltaTi Research (Italy); Frabboni, Stefano; Ottaviani, Giampiero [Department of Physics, University of Modena and Reggio Emilia, via Campi 213, 41100 Modena (Italy)

    2012-09-15

    Energy filtering has been widely considered as a suitable tool to increase the thermoelectric performances of several classes of materials. In its essence, energy filtering provides a way to increase the Seebeck coefficient by introducing a strongly energy-dependent scattering mechanism. Under certain conditions, however, potential barriers may lead to carrier localization, that may also affect the thermoelectric properties of a material. A model is proposed, actually showing that randomly distributed potential barriers (as those found, e.g., in polycrystalline films) may lead to the simultaneous occurrence of energy filtering and carrier localization. Localization is shown to cause a decrease of the actual carrier density that, along with the quantum tunneling of carriers, may result in an unexpected increase of the power factor with the doping level. The model is corroborated toward experimental data gathered by several authors on degenerate polycrystalline silicon and lead telluride. - Graphical abstract: In heavily doped semiconductors potential barriers may lead to both carrier energy filtering and localization. This may lead to an enhancement of the thermoelectric properties of the material, resulting in an unexpected increase of the power factor with the doping level. Highlights: Black-Right-Pointing-Pointer Potential barriers are shown to lead to carrier localization in thermoelectric materials. Black-Right-Pointing-Pointer Evidence is put forward of the formation of a mobility edge. Black-Right-Pointing-Pointer Energy filtering and localization may explain the enhancement of power factor in degenerate semiconductors.

  20. [Social mobilization].

    Science.gov (United States)

    Bop, C

    1990-04-01

    One of the principal recommendations from Alma Ata and the Bamako Initiative was the need for communities to take responsibility for their own health--a recommendation that still remains unmet and in need of reform in Africa because of the severe economic recession and lack of resources allocated for health care in the region. The mobilization of communities "is the opposite of passivity and submission." People must demystify the notion that health care is the exclusive right of health professionals and should realize that they themselves can bring about changes from the household to the village levels; community mobilization is an integral component of development planning. African societies have developed very centralized structures requiring changes that only their own communities can bring about. Because women remain the principal agents for the family's health they should be informed, about the multiple dimensions leading to good health care to enable them to provide the rest of the family with good nourishment and health care follow-up. Children are a vulnerable and important group that require preventive care. A UNICEF experiment in Senegal is training 10-13 year old school children to visit the parents of 5 children, inform them about vaccinating their children, and to follow-up on their activities with these "adopted families." The need for short and long-term IEC interventions in Africa are a priority and effective strategies must be found to reach the majority of the rural populations where all obstacles such as the lack of infrastructure and illiteracy exist. Mali has used traditional theatre "Koteba" to reach the rural populations on a variety of health issues such as oral rehydration and diarrhea as well as the Rural Audio Library (it used cassettes rather than books) to reach villagers in their own languages. The worst obstacle facing Africa today is the refusal of officials in power to allow people to manage their own lives, of which health is a

  1. Cyclodextrins in drug carrier systems.

    Science.gov (United States)

    Uekama, K; Otagiri, M

    1987-01-01

    One of the important characteristics of cyclodextrins is the formation of an inclusion complex with a variety of drug molecules in solution and in the solid state. As a consequence of intensive basic research, exhaustive toxic studies, and realization of industrial production during the past decade, there seem to be no more barriers for the practical application of natural cyclodextrins in the biomedical field. Recently, a number of cyclodextrin derivatives and cyclodextrin polymers have been prepared to obtain better inclusion abilities than parent cyclodextrins. The natural cyclodextrins and their synthetic derivatives have been successfully utilized to improve various drug properties, such as solubility, dissolution and release rates, stability, or bioavailability. In addition, the enhancement of drug activity, selective transfer, or the reduction of side effects has been achieved by means of inclusion complexation. The drug-cyclodextrin complex is generally formed outside of the body and, after administration, it dissociates, releasing the drug into the organism in a fast and nearly uniform manner. In the biomedical application of cyclodextrins, therefore, particular attention should be directed to the magnitude of the stability constant of the inclusion complex. In the case of parenteral application, a rather limited amount of work has been done because the cyclodextrins in the drug carrier systems have to be more effectively designed to compete with various biological components in the circulatory system. However, the works published thus far apparently indicate that the inclusion phenomena of cyclodextrin analogs may allow the rational design of drug formulation and that the combination of molecular encapsulation with other carrier systems will become a very effective and valuable method for the development of a new drug delivery system in the near future.

  2. Mobile OS Comparative Study

    OpenAIRE

    Joseph, Jyothy; K, Shinto Kurian

    2013-01-01

    In the fast growing mobile revolutionary era, many operating systems are playing vital role in present market. This study is intending to identify the apt and secure mobile based on mobile operating systems capability and user requirements.

  3. Mobile Inquiry Based Learning

    NARCIS (Netherlands)

    Specht, Marcus

    2012-01-01

    Specht, M. (2012, 8 November). Mobile Inquiry Based Learning. Presentation given at the Workshop "Mobile inquiry-based learning" at the Mobile Learning Day 2012 at the Fernuniversität Hagen, Hagen, Germany.

  4. MOBILITY: A SYSTEMS APPROACH

    Directory of Open Access Journals (Sweden)

    Mykola I. Striuk

    2015-10-01

    Full Text Available A comprehensive study on the problem of mobility in the socio-educational and technical systems was carried out: the evolution of the concept of mobility in scientific sources of XIX–XXI centuries was analyzed and the new sources on the issue of mobility introduced into scientific circulation, the interrelation of the types of mobility in the socio-pedagogical and technical systems are theoretically grounded, an integrative model of mobility in the information society is proposed. The major trends in academic mobility are identified (the transition from student mobility to mobility programs and educational services providers, the new mobility programs (franchising, double/joint degrees, combinations, nostrification etc. are characterized. The new types of mobility providers are reviewed and attention is focused on virtual universities that are now the basis of virtual mobility of students and activities which are based on the use of new ICT in higher education, especially – the Internet and mobile learning environments.

  5. Micro Mobility Marketing

    DEFF Research Database (Denmark)

    Hosbond, Jens Henrik; Skov, Mikael B.

    2008-01-01

    , in our case a medium-sized retail supermarket. Two prototypes based on push and pull marketing strategies are implemented and evaluated. Taking outset in a synthesis of central issues in contemporary research on mobile marketing, we discuss their role in micro mobility marketing to point to similarities......Mobile marketing refers to marketing of services or goods using mobile technology and mobile marketing holds potentially great economical opportunities. Traditionally, mobile marketing has been viewed as mobility in the large taking place virtually anywhere, anytime. Further, research shows...... considerable number of studies on push-based SMS mobile marketing campaigns. This paper explores a related yet different form of mobile marketing namely micro mobility marketing. Micro mobility marketing denotes mobility in the small, meaning that promotion of goods takes place within a circumscribed location...

  6. Evaluation of electron mobility in InSb quantum wells by means of percentage-impact

    International Nuclear Information System (INIS)

    Mishima, T. D.; Edirisooriya, M.; Santos, M. B.

    2014-01-01

    In order to quantitatively analyze the contribution of each scattering factor toward the total carrier mobility, we use a new convenient figure-of-merit, named a percentage impact. The mobility limit due to a scattering factor, which is widely used to summarize a scattering analysis, has its own advantage. However, a mobility limit is not quite appropriate for the above purpose. A comprehensive understanding of the difference in contribution among many scattering factors toward the total carrier mobility can be obtained by evaluating percentage impacts of scattering factors, which can be straightforwardly calculated from their mobility limits and the total mobility. Our percentage impact analysis shows that threading dislocation is one of the dominant scattering factors for the electron transport in InSb quantum wells at room temperature

  7. Decoupling single nanowire mobilities limited by surface scattering and bulk impurity scattering

    International Nuclear Information System (INIS)

    Khanal, D. R.; Levander, A. X.; Wu, J.; Yu, K. M.; Liliental-Weber, Z.; Walukiewicz, W.; Grandal, J.; Sanchez-Garcia, M. A.; Calleja, E.

    2011-01-01

    We demonstrate the isolation of two free carrier scattering mechanisms as a function of radial band bending in InN nanowires via universal mobility analysis, where effective carrier mobility is measured as a function of effective electric field in a nanowire field-effect transistor. Our results show that Coulomb scattering limits effective mobility at most effective fields, while surface roughness scattering only limits mobility under very high internal electric fields. High-energy α particle irradiation is used to vary the ionized donor concentration, and the observed decrease in mobility and increase in donor concentration are compared to Hall effect results of high-quality InN thin films. Our results show that for nanowires with relatively high doping and large diameters, controlling Coulomb scattering from ionized dopants should be given precedence over surface engineering when seeking to maximize nanowire mobility.

  8. Mobile Search and Advertising

    OpenAIRE

    Lovitskii, Vladimir; McCaffery, Colin; Thrasher, Michael; Traynor, David; Wright, Peter

    2009-01-01

    Mobile advertising is a rapidly growing sector providing brands and marketing agencies the opportunity to connect with consumers beyond traditional and digital media and instead communicate directly on their mobile phones. Mobile advertising will be intrinsically linked with mobile search, which has transported from the internet to the mobile and is identified as an area of potential growth. The result of mobile searching show that as a general rule such search result exceed 1...

  9. Trends in Mobile Marketing

    OpenAIRE

    Chocholová, Petra

    2010-01-01

    The principal aim of this thesis is to assess the state of the mobile marketing as of the first quarter of 2011 and to discuss various scenarios of the future development. This thesis defines the terms "mobile marketing" and "mobile advertising" and identifies the main players in the industry. It explores the main categories of mobile advertising such as mobile messaging, in-content and mobile internet advertising. Later, it analyzes the latest trends in the industry and describes in detail t...

  10. Mobile Communication, Public Participation and E-Governance in China

    DEFF Research Database (Denmark)

    Liu, Jun; Zhao, Hui

    2010-01-01

    China has become the biggest mobile communication carrier in the world since 2001. Advanced technologies create a communication revolution, and the individual, through the advent of mobile media, has become an active participant in this process. This study investigates the mobile phone’s impact...... upon the developments of public participation, social inclusion and citizenship through the case study of Xiamen PX demonstration. In terms of local environmental activism, the Xiamen residents shared information with the help of wireless communication about the alleged misdeeds of party officials...

  11. New approach for measuring the microwave Hall mobility of semiconductors

    International Nuclear Information System (INIS)

    Murthy, D. V. B.; Subramanian, V.; Murthy, V. R. K.

    2006-01-01

    Measurement of Hall mobility in semiconductor samples using bimodal cavity method gives distinct advantages due to noncontact nature as well as the provision to measure anisotropic mobility. But the measurement approaches followed till now have a disadvantage of having high error values primarily due to the problem in evaluating the calibration constant of the whole experimental arrangement. This article brings out a new approach that removes such disadvantage and presents the calibration constant with 1% accuracy. The overall error in the carrier mobility values is within 5%

  12. Carrier-carrier relaxation kinetics in quantum well semiconductor structures with nonparabolic energy bands

    DEFF Research Database (Denmark)

    Dery, H.; Tromborg, Bjarne; Eisenstein, G.

    2003-01-01

    We describe carrier-carrier scattering dynamics in an inverted quantum well structure including the nonparabolic nature of the valance band. A solution of the semiconductor Bloch equations yields strong evidence to a large change in the temporal evolution of the carrier distributions compared to ...

  13. Facilitated transport of hydrophilic salts by mixtures of anion and cation carriers and by ditopic carriers

    NARCIS (Netherlands)

    Chrisstoffels, L.A.J.; de Jong, Feike; Reinhoudt, David; Sivelli, Stefano; Gazzola, Licia; Casnati, Alessandro; Ungaro, Rocco

    1999-01-01

    Anion transfer to the membrane phase affects the extraction efficiency of salt transport by cation carriers 1 and 3. Addition of anion receptors 5 or 6 to cation carriers 1, 3, or 4 in the membrane phase enhances the transport of salts under conditions in which the cation carriers alone do not

  14. Charge carrier transport and photogeneration in P3HT:PCBM photovoltaic blends.

    Science.gov (United States)

    Laquai, Frédéric; Andrienko, Denis; Mauer, Ralf; Blom, Paul W M

    2015-06-01

    This article reviews the charge transport and photogeneration in bulk-heterojunction solar cells made from blend films of regioregular poly(3-hexylthiophene) (RR-P3HT) and methano-fullerene (PCBM). The charge transport, specifically the hole mobility in the RR-P3HT phase of the polymer:fullerene photovoltaic blend, is dramatically affected by thermal annealing. The hole mobility increases more than three orders of magnitude and reaches a value of up to 2 × 10(-4) cm(2) V(-1) s(-1) after the thermal annealing process as a result of an improved semi-crystallinity of the film. This significant increase of the hole mobility balances the electron and hole mobilities in a photovoltaic blend in turn reducing space-charge formation, and this is the most important factor for the strong enhancement of the photovoltaic efficiency compared to an as cast, that is, non-annealed device. In fact, the balanced charge carrier mobility in RR-P3HT:PCBM blends in combination with a field- and temperature-independent charge carrier generation and greatly reduced non-geminate recombination explains the large quantum efficiencies mea-sured in P3HT:PCBM photovoltaic devices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Charge Carrier Transport and Photogeneration in P3HT:PCBM Photovoltaic Blends

    KAUST Repository

    Laquai, Frederic

    2015-05-03

    This article reviews the charge transport and photogeneration in bulk-heterojunction solar cells made from blend films of regioregular poly(3-hexylthiophene) (RR-P3HT) and methano­fullerene (PCBM). The charge transport, specifically the hole mobility in the RR-P3HT phase of the polymer:fullerene photovoltaic blend, is dramatically affected by thermal annealing. The hole mobility increases more than three orders of magnitude and reaches a value of up to 2 × 10−4 cm2 V−1 s−1 after the thermal annealing process as a result of an improved semi-crystallinity of the film. This significant increase of the hole mobility balances the electron and hole mobilities in a photovoltaic blend in turn reducing space-charge formation, and this is the most important factor for the strong enhancement of the photovoltaic efficiency compared to an as cast, that is, non-annealed device. In fact, the balanced charge carrier mobility in RR-P3HT:PCBM blends in combination with a field- and temperature-independent charge carrier generation and greatly reduced non-geminate recombination explains the large quantum efficiencies mea­sured in P3HT:PCBM photovoltaic devices.

  16. The effect of charged quantum dots on the mobility of a two-dimensional electron gas: How important is the Coulomb scattering?

    International Nuclear Information System (INIS)

    Kurzmann, A.; Beckel, A.; Lorke, A.; Geller, M.; Ludwig, A.; Wieck, A. D.

    2015-01-01

    We have investigated the influence of a layer of charged self-assembled quantum dots (QDs) on the mobility of a nearby two-dimensional electron gas (2DEG). Time-resolved transconductance spectroscopy was used to separate the two contributions of the change in mobility, which are: (i) The electrons in the QDs act as Coulomb scatterers for the electrons in the 2DEG. (ii) The screening ability and, hence, the mobility of the 2DEG decreases when the charge carrier density is reduced by the charged QDs, i.e., the mobility itself depends on the charge carrier concentration. Surprisingly, we find a negligible influence of the Coulomb scattering on the mobility for a 2DEG, separated by a 30 nm tunneling barrier to the layer of QDs. This means that the mobility change is completely caused by depletion, i.e., reduction of the charge carrier density in the 2DEG, which indirectly influences the mobility

  17. Driver citation/carrier data relationship project

    Science.gov (United States)

    1996-09-01

    The Driver/Carrier Relationship Project was commissioned to address three issues. The first was to determine if drivers of commercial motor vehicles get tickets at a different rate, depending on the carrier that they are working for. The second issue...

  18. Method and apparatus for information carrier authentication

    NARCIS (Netherlands)

    2015-01-01

    The present invention relates to a method of enabling authentication of an information carrier, the information carrier comprising a writeable part and a physical token arranged to supply a response upon receiving a challenge, the method comprising the following steps; applying a first challenge to

  19. Immobilisation of Acinetobacter calcoaceticus using natural carriers

    African Journals Online (AJOL)

    2005-04-02

    Apr 2, 2005 ... and Cloete, 1995) or ceramic (Kariminiaae-Hamedaani et al.,. 2003) carriers. Besides the synthetic carriers, natural zeolite. (NZ) has been shown as a .... ing 9 mℓ of sterile distilled water, crushed with a sterile glass rod and dispersed by mixing (2 700 r/min for 10 min using the test tube shaker Kartell TK3S) ...

  20. High capacity carrier ethernet transport networks

    DEFF Research Database (Denmark)

    Rasmussen, Anders; Zhang, Jiang; Yu, Hao

    2009-01-01

    OAM functions, survivability and the increased bandwidth requirements of carrier class systems. This article provides an overview of PBB-TE and T-MPLS and demonstrates how IPTV services can be realized in the framework of Carrier Ethernet. In addition we provide a case study on performing bit error...

  1. Providing resilience for carrier ethernet multicast traffic

    DEFF Research Database (Denmark)

    Ruepp, Sarah Renée; Wessing, Henrik; Zhang, Jiang

    2009-01-01

    This paper presents an overview of the Carrier Ethernet technology with specific focus on resilience. In particular, we detail how multicast traffic, which is essential for e.g. IPTV can be protected. We present Carrier Ethernet resilience methods for linear and ring networks and show by simulation...

  2. Inert carrier drying and coating process

    International Nuclear Information System (INIS)

    1980-01-01

    An inert carrier process is described for drying radioactive (particularly low level) waste material and for incorporating the dry material into a binder matrix from which the dried material will not be leached. Experimental details, and examples of the carrier and binder materials, are given. (U.K.)

  3. Theoretical interpretation of the electron mobility behavior in InAs nanowires

    International Nuclear Information System (INIS)

    Marin, E. G.; Ruiz, F. G.; Godoy, A.; Tienda-Luna, I. M.; Martínez-Blanque, C.; Gámiz, F.

    2014-01-01

    This work studies the electron mobility in InAs nanowires (NWs), by solving the Boltzmann Transport Equation under the Momentum Relaxation Time approximation. The numerical solver takes into account the contribution of the main scattering mechanisms present in III-V compound semiconductors. It is validated against experimental field effect-mobility results, showing a very good agreement. The mobility dependence on the nanowire diameter and carrier density is analyzed. It is found that surface roughness and polar optical phonons are the scattering mechanisms that mainly limit the mobility behavior. Finally, we explain the origin of the oscillations observed in the mobility of small NWs at high electric fields.

  4. Theoretical interpretation of the electron mobility behavior in InAs nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Marin, E. G., E-mail: egmarin@ugr.es; Ruiz, F. G., E-mail: franruiz@ugr.es; Godoy, A.; Tienda-Luna, I. M.; Martínez-Blanque, C.; Gámiz, F. [Departamento de Electrónica y Tecnología de los Computadores, Facultad de Ciencias, Universidad de Granada, Av. Fuentenueva S/N, 18071 Granada (Spain)

    2014-11-07

    This work studies the electron mobility in InAs nanowires (NWs), by solving the Boltzmann Transport Equation under the Momentum Relaxation Time approximation. The numerical solver takes into account the contribution of the main scattering mechanisms present in III-V compound semiconductors. It is validated against experimental field effect-mobility results, showing a very good agreement. The mobility dependence on the nanowire diameter and carrier density is analyzed. It is found that surface roughness and polar optical phonons are the scattering mechanisms that mainly limit the mobility behavior. Finally, we explain the origin of the oscillations observed in the mobility of small NWs at high electric fields.

  5. Minority carrier diffusion length extraction in Cu2ZnSn(Se,S)4 solar cells

    Science.gov (United States)

    Gokmen, Tayfun; Gunawan, Oki; Mitzi, David B.

    2013-09-01

    We report measurement of minority carrier diffusion length (Ld) for high performance Cu2ZnSn(S,Se)4 (CZTSSe) solar cells in comparison with analogous Cu(In,Ga)(S,Se)2 (CIGSSe) devices. Our Ld extraction method involves performing systematic measurements of the internal quantum efficiency combined with separate capacitance-voltage measurement. This method also enables the measurement of the absorption coefficient of the absorber material as a function of wavelength in a finished device. The extracted values of Ld for CZTSSe samples are at least factor of 2 smaller than those for CIGSSe samples. Combined with minority carrier lifetime (τ) data measured by time-resolved photoluminescence, we deduce the minority carrier mobility (μe), which is also relatively low for the CZTSSe samples.

  6. Carrier effect on separation efficiency of the column in reversed-phase partition chromatography

    International Nuclear Information System (INIS)

    Pszonicka, M.; Siekierski, S.

    1972-01-01

    Chromatographic columns were filled with carriers of diatomaceous earth type (Hyflo Super Cell, and Celite 545) of large pores, and two microporous silica gels respectively. These columns were used for the separation of europium and gadolinium by reversed-phase partition chromatography in the system: stationary phase-diethylhexylphosphoric acid (HDEHP) mobile phase-0.4 N nitric acid. In each case the separation of the above mentioned elements was achieved. The plate height that characterizes separation efficiency of the column, decreases with the decrease of particle diameter of the carrier. Best columns were obtained from carriers of large pores (Hyflo Super Cell and Celite 545) for which plate hights below 0.1 mm could be achieved. Columns filled with microporous silica gels showed plate heights of 0.2-0.3 mm. (author)

  7. Intrinsic broadening of the mobility spectrum of bulk n-type GaAs

    International Nuclear Information System (INIS)

    Jolley, G; Umana-Membreno, G A; Akhavan, N D; Antoszewski, J; Faraone, L; Fischetti, M V

    2014-01-01

    Modern devices consisting of multiple semiconductor layers often result in the population of numerous distinct carrier species. Conventional Hall measurements at a single-magnetic-field strength provide only a weighted average of the electron mobility and carrier concentration of a semiconductor structure and, therefore, are of limited use for the extraction of carrier transport information. In recent years, mobility spectrum analysis techniques, which have been developed to extract a mobility spectrum from magnetic field-dependent conductivity-tensor measurements, have been applied in the analysis of carrier conductivity mechanisms of numerous semiconductor structures and devices. Currently there is a severe lack of reported studies on theoretical calculations of the mobility distribution of semiconductor structures or devices. In addition, the majority of reports on experimental mobility spectrum analysis are of complex, multi layered structures such as type-II superlattices, and the interpretation of the mobility spectra has been difficult. Therefore, a good understanding of the mobility spectrum has yet to be developed. For example, it is often assumed that distinct peaks of a mobility spectrum result from fundamentally different conduction mechanisms such as the bulk and surface conduction of narrow-band-gap semiconductors. In this article, we present calculations of the electron mobility distribution of bulk GaAs, which predict the existence of multiple mobility spectrum peaks that result from electron conductivity in the Γ conduction band. This report serves as an important and simple test case upon which experimentally measured mobility spectra can be compared. It also presents insight into the general nature of electron mobility distributions. (paper)

  8. Safety requirements for the Pu carriers

    International Nuclear Information System (INIS)

    Mishima, H.

    1993-01-01

    Ministry of Transport of Japan has now set about studying requirements for Pu carriers to ensure safety. It was first studied what the basic concept of safe carriage of Pu should be, and the basic ideas have been worked out. Next the requirements for the Pu carriers were studied based on the above. There are at present no international requirements of construction and equipment for the nuclear-material carriers, but MOT of Japan has so far required special construction and equipment for the nuclear-material carriers which carry a large amount of radioactive material, such as spent fuel or low level radioactive waste, corresponding to the level of the respective potential hazard. The requirements of construction and equipment of the Pu carriers have been established considering the difference in heat generation between Pu and spent fuel, physical protection, and so forth, in addition to the above basic concept. (J.P.N.)

  9. Optimizations in Heterogeneous Mobile Networks

    DEFF Research Database (Denmark)

    Popovska Avramova, Andrijana

    nodes. The independent control of the user’s transmit power at each node may cause degradation of the overall performance. In this line, a dedicated study of power distribution among the carriers is performed. An optimization of the power allocation is proposed and evaluated. The results show...... significant performance improvement to the achieved user throughput in low as well as in high loads in the cell. The flow control of the data between the nodes is another challenge for effective aggregation of the resources in case of dual connectivity. As such, this thesis discusses the challenges...... with the densification of the base stations, bring into a very complex network management and operation control for the mobile operators. Furthermore, the need to provide always best connection and service with high quality demands for a joint overall network resource management. This thesis addresses this challenge...

  10. First-principles calculations of mobility

    Science.gov (United States)

    Krishnaswamy, Karthik

    First-principles calculations can be a powerful predictive tool for studying, modeling and understanding the fundamental scattering mechanisms impacting carrier transport in materials. In the past, calculations have provided important qualitative insights, but numerical accuracy has been limited due to computational challenges. In this talk, we will discuss some of the challenges involved in calculating electron-phonon scattering and carrier mobility, and outline approaches to overcome them. Topics will include the limitations of models for electron-phonon interaction, the importance of grid sampling, and the use of Gaussian smearing to replace energy-conserving delta functions. Using prototypical examples of oxides that are of technological importance-SrTiO3, BaSnO3, Ga2O3, and WO3-we will demonstrate computational approaches to overcome these challenges and improve the accuracy. One approach that leads to a distinct improvement in the accuracy is the use of analytic functions for the band dispersion, which allows for an exact solution of the energy-conserving delta function. For select cases, we also discuss direct quantitative comparisons with experimental results. The computational approaches and methodologies discussed in the talk are general and applicable to other materials, and greatly improve the numerical accuracy of the calculated transport properties, such as carrier mobility, conductivity and Seebeck coefficient. This work was performed in collaboration with B. Himmetoglu, Y. Kang, W. Wang, A. Janotti and C. G. Van de Walle, and supported by the LEAST Center, the ONR EXEDE MURI, and NSF.

  11. Methanol as an energy carrier

    Energy Technology Data Exchange (ETDEWEB)

    Biedermann, P.; Grube, T.; Hoehlein, B. (eds.)

    2006-07-01

    For the future, a strongly growing energy demand is expected in the transport sector worldwide. Economically efficient oil production will run through a maximum in the next decade. Higher fuel prices and an environmentally desirable reduction of emissions will increase the pressure for reducing fuel consumption and emissions in road traffic. These criteria show the urgent necessity of structural changes in the fuel market. Due to its advantages concerning industrial-scale production, storage and global availability, methanol has the short- to medium-term potential for gaining increased significance as a substitution product in the energy market. Methanol can be produced both from fossil energy sources and from biomass or waste materials through the process steps of synthesis gas generation with subsequent methanol synthesis. Methanol has the potential to be used in an environmentally friendly manner in gasoline/methanol mixtures for flexible fuel vehicles with internal combustion engines and in diesel engines with pure methanol. Furthermore, it can be used in fuel cell vehicles with on-board hydrogen production in direct methanol fuel cell drives, and in stationary systems for electricity and heat generation as well as for hydrogen production. Finally, in portable applications it serves as an energy carrier for electric power generation. In this book, the processes for the production and use of methanol are presented and evaluated, markets and future options are discussed and issues of safety and environmental impacts are addressed by a team of well-known authors. (orig.)

  12. Low-temperature mobility measurements on CMOS devices

    International Nuclear Information System (INIS)

    Hairpetian, A.; Gitlin, D.; Viswanathan, C.R.

    1989-01-01

    The surface channel mobility of carriers in eta- and rho-MOS transistors fabricated in a CMOS process was accurately determined at low temperatures down to 5 Κ. The mobility was obtained by an accurate measurement of the inversion charge density using a split C-V technique and the conductance at low drain voltages. The split C-V technique was validated at all temperatures using a one-dimensional Poisson solver (MOSCAP), which was modified for low-temperature application. The mobility dependence on the perpendicular electric field for different substrate bias values appears to have different temperature dependence for eta- and rho-channel devices. The electron mobility increases with a decrease in temperature at all gate voltages. On the other hand, the hole mobility exhibits a different temperature behavior depending upon whether the gate voltage corresponds to strong inversion or is near threshold

  13. Charge carrier transport properties in layer structured hexagonal boron nitride

    Directory of Open Access Journals (Sweden)

    T. C. Doan

    2014-10-01

    Full Text Available Due to its large in-plane thermal conductivity, high temperature and chemical stability, large energy band gap (˜ 6.4 eV, hexagonal boron nitride (hBN has emerged as an important material for applications in deep ultraviolet photonic devices. Among the members of the III-nitride material system, hBN is the least studied and understood. The study of the electrical transport properties of hBN is of utmost importance with a view to realizing practical device applications. Wafer-scale hBN epilayers have been successfully synthesized by metal organic chemical deposition and their electrical transport properties have been probed by variable temperature Hall effect measurements. The results demonstrate that undoped hBN is a semiconductor exhibiting weak p-type at high temperatures (> 700 °K. The measured acceptor energy level is about 0.68 eV above the valence band. In contrast to the electrical transport properties of traditional III-nitride wide bandgap semiconductors, the temperature dependence of the hole mobility in hBN can be described by the form of μ ∝ (T/T0−α with α = 3.02, satisfying the two-dimensional (2D carrier transport limit dominated by the polar optical phonon scattering. This behavior is a direct consequence of the fact that hBN is a layer structured material. The optical phonon energy deduced from the temperature dependence of the hole mobility is ħω = 192 meV (or 1546 cm-1, which is consistent with values previously obtained using other techniques. The present results extend our understanding of the charge carrier transport properties beyond the traditional III-nitride semiconductors.

  14. Scattering and mobility in indium gallium arsenide channel, pseudomorphic high electron mobility transistors (InGaAs pHEMTs)

    International Nuclear Information System (INIS)

    Pearson, J.L.

    1999-03-01

    Extensive transport measurements have been completed on deep and shallow-channelled InGaAs p-HEMTs of varying growth temperature, indium content, spacer thickness and doping density, with a view to a thorough characterisation, both in the metallic and the localised regimes. Particular emphasis was given to MBE grown layers, with characteristics applicable for device use, but low measurement temperatures were necessary to resolve the elastic scattering mechanisms. Measurements made in the metallic regime included transport and quantum mobility - the former over a range of temperatures between 1.5K to 300K. Conductivity measurements were also acquired in the strong localisation regime between about 1.5K and 100K. Experimentally determined parameters were tested for comparison with those predicted by an electrostatic model. Excellent agreement was obtained for carrier density. Other parameters were less well predicted, but the relevant experimental measurements, including linear depletion of the 2DEG, were sensitive to any excess doping above a 'critical' value determined by the model. At low temperature (1.5K), it was found that in all samples tested, transport mobility was strongly limited at all carrier densities by a large q mechanism, possibly intrinsic to the channel. This was ascribed either to scattering by the long-range potentials arising from the indium concentration fluctuations or fluctuations in the thickness of the channel layer. This mechanism dominates the transport at low carrier densities for all samples, but at high carrier density, an additional mechanism is significant for samples with the thinnest spacers tested (2.5nm). This is ascribed to direct electron interaction with the states of the donor layer, and produces a characteristic transport mobility peak. At higher carrier densities, past the peak, quantum mobility was found only to increase monotonically in value. Remote ionised impurity scattering while significant, particularly for samples

  15. Vector Magnetometer Application with Moving Carriers

    Directory of Open Access Journals (Sweden)

    Andrii Prystai

    2016-12-01

    Full Text Available In magnetic prospecting the aeromagnetic survey is a widespread method used for research in large territories or in the areas with difficult access (forests, swamps, shallow waters. At present, a new type of mobile carriers – remotely piloted vehicles or drones – is becoming very common. The drones supplied by magnetometer can be also used for underground utility location (for example, steel and concrete constructions, buried power cables, to name a few. For aeromagnetic survey, obtaining of 3-component magnetic field data gives higher processing precision, so the fluxgate magnetometers (FGM seem to be the most preferable by reason of low weight, noise, power consumption and costs. During movement of FGM fixed to a drone practically permanent attitude changes in the Earth’s magnetic field arises with corresponding changes of its projection at FGM axes. Also the electromagnetic interference from the drone motor and uncontrolled oscillations of drone and suspension are the factors which limit the magnetometer sensitivity level. Aroused because of this, signals significantly exceed the expected signals from a studied object and so should be removed by proper interference filtration and use of stabilized towed construction, as well as at data processing. To find the necessary resolution threshold of a drone-portable FGM, the modeling was made to estimate magnetic field value from a small sphere about 1 cm radius at the minimal altitude of drone flight and it was shown that such a small object can be reliably detected if the FGM noise level is less than 0.15 nT. Next requirement is the necessity to decrease as much as possible the FGM power consumption with retention of low noise level. Finally, because of drone movement, the broadening of a frequency range should be done. The LEMI-026 magnetometer was developed satisfying all requirements to the drone-mounted device. The field tests were successfully performed using two of LEMI-026

  16. Mobile Operating Systems

    OpenAIRE

    Vipin Kamboj; Hitesh Gupta

    2012-01-01

    Mobile phones are used by every people in today’s life. We use mobile phones without knowing the different factors that a mobile used including its technology, operating system, CPU ,RAM etc. Many types of operating system are used by different mobile. Every operating system has their advantage

  17. Mobile Africa : an introduction

    NARCIS (Netherlands)

    Bruijn, de M.E.; Dijk, van R.A.; Foeken, D.W.J.

    2001-01-01

    The case studies in this book on mobility in sub-Saharan Africa critically discuss dichotomous interpretations of mobility and reject the idea that migration indicates a breakdown in society. They adopt the approach that sedentary and mobile worlds converge and that mobility is part of the

  18. Measuring Charge Carrier Diffusion in Coupled Colloidal Quantum Dot Solids

    KAUST Repository

    Zhitomirsky, David

    2013-06-25

    Colloidal quantum dots (CQDs) are attractive materials for inexpensive, room-temperature-, and solution-processed optoelectronic devices. A high carrier diffusion length is desirable for many CQD device applications. In this work we develop two new experimental methods to investigate charge carrier diffusion in coupled CQD solids under charge-neutral, i.e., undepleted, conditions. The methods take advantage of the quantum-size-effect tunability of our materials, utilizing a smaller-bandgap population of quantum dots as a reporter system. We develop analytical models of diffusion in 1D and 3D structures that allow direct extraction of diffusion length from convenient parametric plots and purely optical measurements. We measure several CQD solids fabricated using a number of distinct methods and having significantly different doping and surface ligand treatments. We find that CQD materials recently reported to achieve a certified power conversion efficiency of 7% with hybrid organic-inorganic passivation have a diffusion length of 80 ± 10 nm. The model further allows us to extract the lifetime, trap density, mobility, and diffusion coefficient independently in each material system. This work will facilitate further progress in extending the diffusion length, ultimately leading to high-quality CQD solid semiconducting materials and improved CQD optoelectronic devices, including CQD solar cells. © 2013 American Chemical Society.

  19. Charge Carrier Transport Properties of Vacuum Evaporated Anthrylvinylbenzene Thin Films

    Directory of Open Access Journals (Sweden)

    Haikel HRICHI

    2014-05-01

    Full Text Available The charge carrier conduction processes and dielectric properties of two new materials based on anthracene core structure, 1-(9 anthrylvinyl-4-benzyloxybenzene (AVB and 1,4- bis(9-anthrylvinylbenzene (AV2B diodes have been investigated using dc current density–voltage (J–V and AC impedance spectroscopy (100 Hz–10 MHz. The DC electrical properties of ITO/anthracene derivative /Al device showing an ohmic behavior at low voltages and switches to space charge limited current (SCLC conduction with exponential trap distribution at higher voltages. The best performance device was achieved from ITO/AVB/Al structure showing the high charge carrier mobility which has also been evaluated from SCLC as 6.55´10-6 cm/Vs. According to the impedance spectroscopy results the structures were modeled by equivalent circuit designed as a parallel resistor Rp and capacitor Cp network in series with resistor Rs. The evolution of the electrical parameters with frequency and bias voltage of these anthracene-based systems has been discussed. The conductivity s(w evolution with frequency and bias voltage was studied for ITO/anthracene derivatives/Al devices. The dc conductivity sdc for these devices has been determined. The ac conductivity sac showed a variation in angular frequency as A.ws with a critical exponent s< 1 suggesting a hopping conduction mechanism at high frequency.

  20. Evolution of Mobile Applications

    Directory of Open Access Journals (Sweden)

    Phongtraychack Anachack

    2018-01-01

    Full Text Available Currently, we can see the rapid evolution of mobile technology, which involves mobile communication, mobile hardware, and mobile software. Features of mobile phones largely depend on software. In contemporary information and communication age [1–4], mobile application is one of the most concerned and rapidly developing areas. At the same time, the development of mobile application undergoes great changes with the introduction of new software, service platforms and software development kits (SDK. These changes lead to appearance of many new service platforms such as Google with Android and Apple with iOS. This article presents the information about the evolution of mobile application, gives some statistical data on the past and present situation, demonstrates how individual users of mobile devices can benefit, and shows how mobile applications affect society from the ethical perspective.

  1. MOBILITY: A SYSTEMS APPROACH

    OpenAIRE

    Mykola I. Striuk; Serhiy O. Semerikov; Andrii M. Striuk

    2015-01-01

    A comprehensive study on the problem of mobility in the socio-educational and technical systems was carried out: the evolution of the concept of mobility in scientific sources of XIX–XXI centuries was analyzed and the new sources on the issue of mobility introduced into scientific circulation, the interrelation of the types of mobility in the socio-pedagogical and technical systems are theoretically grounded, an integrative model of mobility in the information society is proposed. The major t...

  2. Mobile platform security

    CERN Document Server

    Asokan, N; Dmitrienko, Alexandra

    2013-01-01

    Recently, mobile security has garnered considerable interest in both the research community and industry due to the popularity of smartphones. The current smartphone platforms are open systems that allow application development, also for malicious parties. To protect the mobile device, its user, and other mobile ecosystem stakeholders such as network operators, application execution is controlled by a platform security architecture. This book explores how such mobile platform security architectures work. We present a generic model for mobile platform security architectures: the model illustrat

  3. Carrier scattering in metals and semiconductors

    CERN Document Server

    Gantmakher, VF

    1987-01-01

    The transport properties of solids, as well as the many optical phenomena in them are determined by the scattering of current carriers. ``Carrier Scattering in Metals and Semiconductors'' elucidates the state of the art in the research on the scattering mechanisms for current carriers in metals and semiconductors and describes experiments in which these mechanisms are most dramatically manifested.The selection and organization of the material is in a form to prepare the reader to reason independently and to deal just as independently with available theoretical results and experimental

  4. Effects of carrier concentrations on the charge transport properties in monolayer silicene

    International Nuclear Information System (INIS)

    Abidin, B I; Yeoh, K H; Yong, T K; Ong, D S

    2017-01-01

    Using analytical band Monte Carlo approach, we have carried out a systematic study on the effects of carrier concentrations on the steady-state and transient electron transports that occur within a monolayer silicene. In particular, we have observed the following: First at steady-state, the electron mobility reduces with higher carrier concentrations. Secondly, in the transient regime we found that the drift velocity overshoot can be controlled by varying the carrier concentrations. We uncover that at carrier concentration of 1  ×  10 13 cm −2 , the drift velocity overshoot can reach up to 3.8  ×  10 7 cm s −1 which is close to the steady-state drift velocity saturation of graphene. Thirdly, the distance of the velocity over shoot can be further extended with higher carrier concentrations. Our findings could be useful and can be used as benchmark for future development of nanoscale silicene based devices. (paper)

  5. Personality traits in Huntington's disease: An exploratory study of gene expansion carriers and non-carriers.

    Science.gov (United States)

    Larsen, Ida Unmack; Mortensen, Erik Lykke; Vinther-Jensen, Tua; Nielsen, Jørgen Erik; Knudsen, Gitte Moos; Vogel, Asmus

    2016-12-01

    Huntington's disease (HD) is associated with risk for developing psychiatric symptoms. Vulnerability or resilience to psychiatric symptoms may be associated with personality traits. This exploratory study, aimed to investigate personality traits in a large cohort of HD carriers and at risk gene-expansion negative individuals (HD non-carriers), exploring whether carrying the HD gene or growing up in an HD family influences personality traits. Forty-seven HD carriers, Thirty-nine HD non-carriers, and 121 healthy controls answered the Danish version of the revised NEO personality inventory. Comparisons between HD carriers and HD non-carriers were mostly non-significant but the combined group of HD carriers and non-carriers showed significantly higher scores on the facets: "hostility," "assertiveness," and "activity" and on the trait "Conscientiousness" relative to controls, "Conscientiousness" have been associated with resilience to psychiatric symptoms. Twelve HD carriers and non-carriers were classified as depressed and showed significantly lower scores on "Extraversion" and "Conscientiousness" and significantly higher scores on "Neuroticism," which are associated with vulnerability to psychiatric symptoms. Our findings suggest that, there is no direct effect of the HD gene on personality traits, but that personality assessment may be relevant to use when identifying individuals from HD families who are vulnerable to develop psychiatric symptoms. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  6. Abrechnung mobiler Dienste im Mobile-Payment-Referenzmodell

    OpenAIRE

    Pousttchi, Key; Wiedemann, Dietmar Georg

    2005-01-01

    The purpose of the paper is to analyze mobile payments in the mobile commerce scenario. Therefore, we first classify the mobile payment in the mobile commerce scenario by explaining general offer models, charging concepts, and intermediaries. Second, we describe the mobile payment reference model, especially, the mobile payment reference organization model and different mobile payment standard types. Finally, we conclude our findings.

  7. Charging of mobile services by mobile payment reference model

    OpenAIRE

    Pousttchi, Key; Wiedemann, Dietmar Georg

    2005-01-01

    The purpose of the paper is to analyze mobile payments in the mobile commerce scenario. Therefore, we first classify the mobile payment in the mobile commerce scenario by explaining general offer models, charging concepts, and intermediaries. Second, we describe the mobile payment reference model, especially, the mobile payment reference organization model and different mobile payment standard types. Finally, we conclude our findings.

  8. On the Comparative Performance Analysis of Turbo-Coded Non-Ideal Sigle-Carrier and Multi-Carrier Waveforms over Wideband Vogler-Hoffmeyer HF Channels

    Directory of Open Access Journals (Sweden)

    F. Genc

    2014-09-01

    Full Text Available The purpose of this paper is to compare the turbo-coded Orthogonal Frequency Division Multiplexing (OFDM and turbo-coded Single Carrier Frequency Domain Equalization (SC-FDE systems under the effects of Carrier Frequency Offset (CFO, Symbol Timing Offset (STO and phase noise in wide-band Vogler-Hoffmeyer HF channel model. In mobile communication systems multi-path propagation occurs. Therefore channel estimation and equalization is additionally necessary. Furthermore a non-ideal local oscillator generally is misaligned with the operating frequency at the receiver. This causes carrier frequency offset. Hence in coded SC-FDE and coded OFDM systems; a very efficient, low complex frequency domain channel estimation and equalization is implemented in this paper. Also Cyclic Prefix (CP based synchronization synchronizes the clock and carrier frequency offset.The simulations show that non-ideal turbo-coded OFDM has better performance with greater diversity than non-ideal turbo-coded SC-FDE system in HF channel.

  9. Auto Carrier Transporter Loading and Unloading Improvement

    National Research Council Canada - National Science Library

    Miller, Brian

    2003-01-01

    .... Any reduction in time and energy will result in a significant savings of money. The intent of this research is to develop an algorithm to solve the Auto Carrier Transport Pickup and Delivery Problem...

  10. Aircraft Carrier Exposure Testing of Aircraft Materials

    National Research Council Canada - National Science Library

    Lee, Eui

    2004-01-01

    .... Test and control specimens were affixed on exposure racks and installed on aircraft carriers to compare adhesive bonding primers for aluminum and to determine the static property behavior of various...

  11. Commercial Air Carrier Vulnerabilities to Information Operations

    National Research Council Canada - National Science Library

    Shelburn, Bryan H

    2002-01-01

    .... Among those elements susceptible to these vulnerabilities are the operations of commercial air carriers that are essential to the military's ability to wage war and project power wherever needed in the world...

  12. Part B Carrier Summary Data File

    Data.gov (United States)

    U.S. Department of Health & Human Services — Data sets are summarized at the carrier level by meaningful Healthcare Common Procedure Coding-Current Procedural Terminology, (HCPC-CPT), code ranges. The data set...

  13. Tunable Mobility in Double-Gated MoTe2 Field-Effect Transistor: Effect of Coulomb Screening and Trap Sites.

    Science.gov (United States)

    Ji, Hyunjin; Joo, Min-Kyu; Yi, Hojoon; Choi, Homin; Gul, Hamza Zad; Ghimire, Mohan Kumar; Lim, Seong Chu

    2017-08-30

    There is a general consensus that the carrier mobility in a field-effect transistor (FET) made of semiconducting transition-metal dichalcogenides (s-TMDs) is severely degraded by the trapping/detrapping and Coulomb scattering of carriers by ionic charges in the gate oxides. Using a double-gated (DG) MoTe 2 FET, we modulated and enhanced the carrier mobility by adjusting the top- and bottom-gate biases. The relevant mechanism for mobility tuning in this device was explored using static DC and low-frequency (LF) noise characterizations. In the investigations, LF-noise analysis revealed that for a strong back-gate bias the Coulomb scattering of carriers by ionized traps in the gate dielectrics is strongly screened by accumulation charges. This significantly reduces the electrostatic scattering of channel carriers by the interface trap sites, resulting in increased mobility. The reduction of the number of effective trap sites also depends on the gate bias, implying that owing to the gate bias, the carriers are shifted inside the channel. Thus, the number of active trap sites decreases as the carriers are repelled from the interface by the gate bias. The gate-controlled Coulomb-scattering parameter and the trap-site density provide new handles for improving the carrier mobility in TMDs, in a fundamentally different way from dielectric screening observed in previous studies.

  14. Nonlinear transport in semiconducting polymers at high carrier densities.

    Science.gov (United States)

    Yuen, Jonathan D; Menon, Reghu; Coates, Nelson E; Namdas, Ebinazar B; Cho, Shinuk; Hannahs, Scott T; Moses, Daniel; Heeger, Alan J

    2009-07-01

    Conducting and semiconducting polymers are important materials in the development of printed, flexible, large-area electronics such as flat-panel displays and photovoltaic cells. There has been rapid progress in developing conjugated polymers with high transport mobility required for high-performance field-effect transistors (FETs), beginning with mobilities around 10(-4) cm(2) V(-1) s(-1) to a recent report of 1 cm(2) V(-1) s(-1) for poly(2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene) (PBTTT). Here, the electrical properties of PBTTT are studied at high charge densities both as the semiconductor layer in FETs and in electrochemically doped films to determine the transport mechanism. We show that data obtained using a wide range of parameters (temperature, gate-induced carrier density, source-drain voltage and doping level) scale onto the universal curve predicted for transport in the Luttinger liquid description of the one-dimensional 'metal'.

  15. Drift of charge carriers in crystalline organic semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Jingjuan; Si, Wei [State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433 (China); Wu, Chang-Qin, E-mail: cqw@fudan.edu.cn [State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433 (China); Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433 (China)

    2016-04-14

    We investigate the direct-current response of crystalline organic semiconductors in the presence of finite external electric fields by the quantum-classical Ehrenfest dynamics complemented with instantaneous decoherence corrections (IDC). The IDC is carried out in the real-space representation with the energy-dependent reweighing factors to account for both intermolecular decoherence and energy relaxation by which conduction occurs. In this way, both the diffusion and drift motion of charge carriers are described in a unified framework. Based on an off-diagonal electron-phonon coupling model for pentacene, we find that the drift velocity initially increases with the electric field and then decreases at higher fields due to the Wannier-Stark localization, and a negative electric-field dependence of mobility is observed. The Einstein relation, which is a manifestation of the fluctuation-dissipation theorem, is found to be restored in electric fields up to ∼10{sup 5} V/cm for a wide temperature region studied. Furthermore, we show that the incorporated decoherence and energy relaxation could explain the large discrepancy between the mobilities calculated by the Ehrenfest dynamics and the full quantum methods, which proves the effectiveness of our approach to take back these missing processes.

  16. Evaluating multicast resilience in carrier ethernet

    DEFF Research Database (Denmark)

    Ruepp, Sarah Renée; Wessing, Henrik; Zhang, Jiang

    2010-01-01

    This paper gives an overview of the Carrier Ethernet technology with specific focus on resilience. In particular, we show how multicast traffic, which is essential for IPTV can be protected. We detail the ackground for resilience mechanisms and their control and e present Carrier Ethernet...... resilience methods for linear nd ring networks. By simulation we show that the vailability of a multicast connection can be significantly increased by applying protection methods....

  17. Synthetic Lipoproteins as Carriers for Drug Delivery.

    Science.gov (United States)

    Huang, Gangliang; Liu, Yang; Huang, Hualiang

    2016-01-01

    Synthetic lipoprotein is an effective carrier of targeted delivery for drugs. It has the very small size, good biocompatibility, suitable half-life, and specific lipoprotein receptorbinding capacity. Compared with the traditional natural lipoprotein, synthetic lipoprotein not only retains the original biological characteristics and functions, but also exhibits the excellent characteristics in drug delivery. Herein, the advantages, development, applications, and prospect of synthetic lipoproteins as drug carriers were summarized.

  18. Thermoelectric transport properties of high mobility organic semiconductors

    Science.gov (United States)

    Venkateshvaran, Deepak; Broch, Katharina; Warwick, Chris N.; Sirringhaus, Henning

    2016-09-01

    Transport in organic semiconductors has traditionally been investigated using measurements of the temperature and gate voltage dependent mobility of charge carriers within the channel of organic field-effect transistors (OFETs). In such measurements, the behavior of charge carrier mobility with temperature and gate voltage, studied together with carrier activation energies, provide a metric to quantify the extent of disorder within these van der Waals bonded materials. In addition to the mobility and activation energy, another potent but often-overlooked transport coefficient useful in understanding disorder is the Seebeck coefficient (also known as thermoelectric power). Fundamentally, the Seebeck coefficient represents the entropy per charge carrier in the solid state, and thus proves powerful in distinguishing materials in which charge carriers move freely from those where a high degree of disorder causes the induced carriers to remain trapped. This paper briefly covers the recent highlights in the field of organic thermoelectrics, showing how significant strides have been made both from an applied standpoint as well as from a viewpoint of fundamental thermoelectric transport physics. It shall be illustrated how thermoelectric transport parameters in organic semiconductors can be tuned over a significant range, and how this tunability facilitates an enhanced performance for heat-to-electricity conversion as well as quantifies energetic disorder and the nature of the density of states (DOS). The work of the authors shall be spotlighted in this context, illustrating how Seebeck coefficient measurements in the polymer indacenodithiophene-co-benzothiadiazole (IDTBT) known for its ultra-low degree of torsion within the polymer backbone, has a trend consistent with low disorder. 1 Finally, using examples of the small molecules C8-BTBT and C10-DNTT, it shall be discussed how the Seebeck coefficient can aid the estimation of the density and distribution of trap states

  19. Hybrid Perovskites for Photovoltaics: Charge-Carrier Recombination, Diffusion, and Radiative Efficiencies.

    Science.gov (United States)

    Johnston, Michael B; Herz, Laura M

    2016-01-19

    Photovoltaic (PV) devices that harvest the energy provided by the sun have great potential as renewable energy sources, yet uptake has been hampered by the increased cost of solar electricity compared with fossil fuels. Hybrid metal halide perovskites have recently emerged as low-cost active materials in PV cells with power conversion efficiencies now exceeding 20%. Rapid progress has been achieved over only a few years through improvements in materials processing and device design. In addition, hybrid perovskites appear to be good light emitters under certain conditions, raising the prospect of applications in low-cost light-emitting diodes and lasers. Further optimization of such hybrid perovskite devices now needs to be supported by a better understanding of how light is converted into electrical currents and vice versa. This Account provides an overview of charge-carrier recombination and mobility mechanisms encountered in such materials. Optical-pump-terahertz-probe (OPTP) photoconductivity spectroscopy is an ideal tool here, because it allows the dynamics of mobile charge carriers inside the perovskite to be monitored following excitation with a short laser pulse whose photon energy falls into the range of the solar spectrum. We first review our insights gained from transient OPTP and photoluminescence spectroscopy on the mechanisms dominating charge-carrier recombination in these materials. We discuss that mono-molecular charge-recombination predominantly originates from trapping of charges, with trap depths being relatively shallow (tens of millielectronvolts) for hybrid lead iodide perovskites. Bimolecular recombination arises from direct band-to-band electron-hole recombination and is found to be in significant violation of the simple Langevin model. Auger recombination exhibits links with electronic band structure, in accordance with its requirement for energy and momentum conservation for all charges involved. We further discuss charge-carrier mobility

  20. Doping dependence and anisotropy of minority electron mobility in molecular beam epitaxy-grown p type GaInP

    Energy Technology Data Exchange (ETDEWEB)

    Haegel, N. M.; Christian, T.; Norman, A. G.; Mascarenhas, A. [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States); Scandrett, C. [Naval Postgraduate School, Monterey, California 93943 (United States); Misra, Pranob; Liu, Ting; Sukiasyan, Arsen; Pickett, Evan; Yuen, Homan [Solar Junction, Inc., San Jose, California 95131 (United States)

    2014-11-17

    Direct imaging of minority electron transport via the spatially resolved recombination luminescence signature has been used to determine carrier diffusion lengths in GaInP as a function of doping. Minority electron mobility values are determined by performing time resolved photoluminescence measurements of carrier lifetime on the same samples. Values at 300 K vary from ∼2000 to 400 cm{sup 2}/V s and decrease with increasing doping. Anisotropic diffusion lengths and strongly polarized photoluminescence are observed, resulting from lateral composition modulation along the [110] direction. We report anisotropic mobility values associated with carrier transport parallel and perpendicular to the modulation direction.

  1. Ultrafast carrier dynamics in a p-type GaN wafer under different carrier distributions

    Science.gov (United States)

    Fang, Yu; Yang, Junyi; Yang, Yong; Wu, Xingzhi; Xiao, Zhengguo; Zhou, Feng; Song, Yinglin

    2016-02-01

    The dependence of the carrier distribution on photoexcited carrier dynamics in a p-type Mg-doped GaN (GaN:Mg) wafer were systematically measured by femtosecond transient absorption (TA) spectroscopy. The homogeneity of the carrier distribution was modified by tuning the wavelength of the UV pulse excitation around the band gap of GaN:Mg. The TA kinetics appeared to be biexponential for all carrier distributions, and only the slower component decayed faster as the inhomogeneity of the carrier distribution increased. It was concluded that the faster component (50-70 ps) corresponded to the trap process of holes by the Mg acceptors, and the slower component (150-600 ps) corresponded to the combination of non-radiative surface recombination and intrinsic carrier recombination via dislocations. Moreover, the slower component increased gradually with the incident fluence due to the saturation of surface states.

  2. The Kinetics of Carrier Transport Inhibition

    DEFF Research Database (Denmark)

    Rosenberg, T.; Wilbrandt, Robert Walter

    1962-01-01

    The kinetical treatment of enzymatic carrier transports as given in previous communications has been extended to conditions of inhibition. Various possible types of inhibitors have been considered differing in the site of attack (enzyme or carrier), in the mode of action (competing with the subst......The kinetical treatment of enzymatic carrier transports as given in previous communications has been extended to conditions of inhibition. Various possible types of inhibitors have been considered differing in the site of attack (enzyme or carrier), in the mode of action (competing...... with the substrate for the enzyme or the carrier or for both, competing with the carrier for the enzyme, or non-competitive) and in the ability of penetrating the membrane. Experiments are reported on the inhibition of glucose and fructose transport across the human red cell membrane by phlorizine, phloretine...... and polyphloretinephosphate. The results of the analysis for these inhibitors indicate a substrate competitive mode of action. The effect of reversing the transport direction by interchanging the substrate concentration has been treated for the case of a non-penetrating substrate competitive inhibitor in the external medium...

  3. Head First Mobile Web

    CERN Document Server

    Gardner, Lyza; Grigsby, Jason

    2011-01-01

    Despite the huge number of mobile devices and apps in use today, your business still needs a website. You just need it to be mobile. Head First Mobile Web walks you through the process of making a conventional website work on a variety smartphones and tablets. Put your JavaScript, CSS media query, and HTML5 skills to work-then optimize your site to perform its best in the demanding mobile market. Along the way, you'll discover how to adapt your business strategy to target specific devices. Navigate the increasingly complex mobile landscapeTake both technical and strategic approaches to mobile

  4. Mobile Portal Implementation Strategy

    DEFF Research Database (Denmark)

    Gao, Ping; Damsgaard, Jan

    2005-01-01

    Mobile portal plays an important role in mobile commerce market. Current literature focuses on static analysis on the value chain of mobile portals. This article provides a dynamic perspective on mobile portal strategy. Drawing upon network economics, we describe mobile portal implementation...... as a fourphase process. In different phase, a portal provider has various challenges to overcome and adopt diverse strategies, and correspondingly the regulator has different foci. The conceptual framework proposed in this article offers a basis for further analyses on the market dynamics of mobile commerce......, and can be generalized to studying other networked technologies...

  5. Understanding morphology-mobility dependence in PEDOT:Tos

    Science.gov (United States)

    Rolland, Nicolas; Franco-Gonzalez, Juan Felipe; Volpi, Riccardo; Linares, Mathieu; Zozoulenko, Igor V.

    2018-04-01

    The potential of conjugated polymers to compete with inorganic materials in the field of semiconductor is conditional on fine-tuning of the charge carriers mobility. The latter is closely related to the material morphology, and various studies have shown that the bottleneck for charge transport is the connectivity between well-ordered crystallites, with a high degree of π -π stacking, dispersed into a disordered matrix. However, at this time there is a lack of theoretical descriptions accounting for this link between morphology and mobility, hindering the development of systematic material designs. Here we propose a computational model to predict charge carriers mobility in conducting polymer PEDOT depending on the physicochemical properties of the system. We start by calculating the morphology using molecular dynamics simulations. Based on the calculated morphology we perform quantum mechanical calculation of the transfer integrals between states in polymer chains and calculate corresponding hopping rates using the Miller-Abrahams formalism. We then construct a transport resistive network, calculate the mobility using a mean-field approach, and analyze the calculated mobility in terms of transfer integrals distributions and percolation thresholds. Our results provide theoretical support for the recent study [Noriega et al., Nat. Mater. 12, 1038 (2013), 10.1038/nmat3722] explaining why the mobility in polymers rapidly increases as the chain length is increased and then saturates for sufficiently long chains. Our study also provides the answer to the long-standing question whether the enhancement of the crystallinity is the key to designing high-mobility polymers. We demonstrate, that it is the effective π -π stacking, not the long-range order that is essential for the material design for the enhanced electrical performance. This generic model can compare the mobility of a polymer thin film with different solvent contents, solvent additives, dopant species or

  6. Probing surface states in PbS nanocrystal films using pentacene field effect transistors: controlling carrier concentration and charge transport in pentacene.

    Science.gov (United States)

    Park, Byoungnam; Whitham, Kevin; Bian, Kaifu; Lim, Yee-Fun; Hanrath, Tobias

    2014-12-21

    We used a bilayer field effect transistor (FET) consisting of a thin PbS nanocrystals (NCs) film interfaced with vacuum-deposited pentacene to probe trap states in NCs. We interpret the observed threshold voltage shift in context of charge carrier trapping by PbS NCs and relate the magnitude of the threshold voltage shift to the number of trapped carriers. We explored a series of NC surface ligands to modify the interface between PbS NCs and pentacene and demonstrate the impact of interface chemistry on charge carrier density and the FET mobility in a pentacene FET.

  7. Ion mobility sensor system

    Science.gov (United States)

    Xu, Jun; Watson, David B.; Whitten, William B.

    2013-01-22

    An ion mobility sensor system including an ion mobility spectrometer and a differential mobility spectrometer coupled to the ion mobility spectrometer. The ion mobility spectrometer has a first chamber having first end and a second end extending along a first direction, and a first electrode system that generates a constant electric field parallel to the first direction. The differential mobility spectrometer includes a second chamber having a third end and a fourth end configured such that a fluid may flow in a second direction from the third end to the fourth end, and a second electrode system that generates an asymmetric electric field within an interior of the second chamber. Additionally, the ion mobility spectrometer and the differential mobility spectrometer form an interface region. Also, the first end and the third end are positioned facing one another so that the constant electric field enters the third end and overlaps the fluid flowing in the second direction.

  8. Seasonality, mobility, and livability.

    Science.gov (United States)

    2012-01-31

    Signature project 4a, Seasonality, Mobility, and Livability investigated the effects of weather, season, built environment, community amenities, attitudes, and demographics on mobility and quality of life (QOL). A four season panel survey exami...

  9. Mobile IP: Security & application

    NARCIS (Netherlands)

    Tuquerres, G.; Salvador, M.R.; Sprenkels, Ron

    1999-01-01

    As required in the TGS Mobile IP Advanced Module, this paper presents a survey of common security threats which mobile IP networks are exposed to as well as some proposed solutions to deal with such threats.

  10. Mobile Phones on Campus

    Institute of Scientific and Technical Information of China (English)

    朴春宝

    2007-01-01

    After entering the 21st century, more and more people have mobile phones in China. At the end of 2002, there were 20 million mobile phone users. By the year 2005 the number has reached up to 30 million.

  11. Mobile Internet Protocol Analysis

    National Research Council Canada - National Science Library

    Brachfeld, Lawrence

    1999-01-01

    ...) and User Datagram Protocol (UDP). Mobile IP allows mobile computers to send and receive packets addressed with their home network IP address, regardless of the IP address of their current point of attachment on the Internet...

  12. Mobile Informal Learning

    NARCIS (Netherlands)

    Glahn, Christian; Börner, Dirk

    2010-01-01

    Glahn, C., & Börner, D. (2009). Mobile Informal Learning. Presented at Mobile Learning in Context Symposium at the Open University of the Netherlands. September, 11, 2009, Heerlen, The Netherlands: Open University of the Netherlands.

  13. Transparent, high mobility InGaZnO thin films deposited by PLD

    International Nuclear Information System (INIS)

    Suresh, Arun; Gollakota, Praveen; Wellenius, Patrick; Dhawan, Anuj; Muth, John F.

    2008-01-01

    Transparent oxide semiconductor, InGaZnO, thin films were prepared by pulsed laser deposition at room temperature. The carrier concentration was found to vary by several orders of magnitude from insulating to 10 19 carriers/cm 3 depending on the oxygen partial pressure during deposition. Hall mobilities as high as 16 cm 2 /V s were observed. This is approximately an order of magnitude higher than the mobility of amorphous silicon and indicates that InGaO 3 (ZnO) x with x ≤ 5 may be suitable for transparent, thin film transistor applications. Post-deposition annealing was found to strongly influence the carrier concentration while annealing effects on the electron mobility was less influential

  14. Steady state minority carrier lifetime and defect level occupation in thin film CdTe solar cells

    International Nuclear Information System (INIS)

    Cheng, Zimeng; Delahoy, Alan E.; Su, Zhaoqian; Chin, Ken K.

    2014-01-01

    A model consisting of Shockley Read Hall (SRH) recombination under steady state conditions of constant photon injection is proposed in this work to study the steady state minority carrier lifetime in CdS/CdTe thin film solar cells. The SRH recombination rate versus optical injection level is analytically approximated in the junction and neutral regions. In the neutral region, it is found that the recombination rate through certain defect levels has one constant value under lower optical injection conditions and another constant value under higher optical injection conditions with the transition occurring at a critical optical injection level. By simultaneously solving the equations of charge neutrality, charge conservation and SRH recombination in the neutral region, it is found that the compensation of doping and the reduction of minority carrier lifetime by donors in the p-type semiconductor can each be remedied by optical injection. It is also demonstrated that this optical-dependent SRH recombination is significant in large bandgap thin films. The measured minority carrier diffusion length in a CdS/CdTe solar cells, as determined from the steady-state photo-generated carrier collection efficiency, shows the predicted transition of minority carrier lifetime versus optical injection level. A numerical fitting of the indirectly-measured minority carrier lifetime by assuming the minority carrier mobility gives a non-intuitive picture of the p–n junction with a low free hole concentration but a narrow depletion region width. - Highlights: • Minority carrier lifetimes under different optical injections are solved. • Simplifications of Shockley–Read–Hall recombination equation are discussed. • The compensation of donor can be remedied with optical injection. • The recombination efficiency of donor can be remedied with optical injection. • The minority carrier lifetime transition under illumination was experimentally observed

  15. Fixed mobile convergence handbook

    CERN Document Server

    Ahson, Syed A

    2010-01-01

    From basic concepts to future directions, this handbook provides technical information on all aspects of fixed-mobile convergence (FMC). The book examines such topics as integrated management architecture, business trends and strategic implications for service providers, personal area networks, mobile controlled handover methods, SIP-based session mobility, and supervisory and notification aggregator service. Case studies are used to illustrate technical and systematic implementation of unified and rationalized internet access by fixed-mobile network convergence. The text examines the technolo

  16. Ion mobility spectrometry

    CERN Document Server

    Eiceman, GA

    2005-01-01

    Key Developments for Faster, More Precise Detection Capabilities Driven by the demand for the rapid and advanced detection of explosives, chemical and biological warfare agents, and narcotics, ion mobility spectrometry (IMS) undergone significant refinements in technology, computational capabilities, and understanding of the principles of gas phase ion chemistry and mobility. Beginning with a thorough discussion of the fundamental theories and physics of ion mobility, Ion Mobility Spectrometry, Second Edition describes the recent advances in instrumentation and newly

  17. Mobile Marketing in Japan

    OpenAIRE

    Noah H. N. Lynn; Paul D. Berger

    2014-01-01

    In this paper we describe the state of mobile marketing in Japan. We consider the various aspects of mobile marketing in Japan and what has led to the overwhelming adoption by Japanese youth, and to a degree Japanese society as a whole, of social media and associated activities. This growth of mobile marketing has dramatic, positive implications for marketing, in general, as well as for the sale of selected product classes. We also consider markers for suggesting what the future of mobile mar...

  18. Performance of Uplink Carrier Aggregation in LTE-Advanced Systems

    DEFF Research Database (Denmark)

    Wang, Hua; Rosa, Claudio; Pedersen, Klaus

    2010-01-01

    Carrier aggregation (CA) has been proposed to aggregate two or more component carriers (CCs) to support a much wider transmission bandwidth for LTE-Advanced systems. With carrier aggregation, it is possible to schedule a user equipment (UE) on multiple component carriers simultaneously. In this p...

  19. Multi-User Interference Cancellation Scheme(s) for Muliple Carrier Frequency Offset Compensation in Uplink OFDMA

    DEFF Research Database (Denmark)

    Nguyen, Huan Cong; Carvalho, Elisabeth De; Prasad, Ramjee

    2006-01-01

    (ICI) and degrade the system performance considerably. In this paper, we propose a novel Multi-User Interference (MUI) cancellation scheme for uplink OFDMA, which utilizes multiple OFDM-demodulators architecture to correct and then compensate the negative effects of multiple CFOs at the receiver's side......We consider the uplink of an Orthogonal Frequency Division Multiple Access (OFDMA)-based system, where each Mobile Station (MS) experiences a different Carrier Frequency Offset (CFO). Uncorrected CFO destroy the orthogonality among subcarriers, which could cause severe Inter-Carrier Interference...

  20. Mobile energy sharing futures

    DEFF Research Database (Denmark)

    Worgan, Paul; Knibbe, Jarrod; Plasencia, Diego Martinez

    2016-01-01

    We foresee a future where energy in our mobile devices can be shared and redistributed to suit our current task needs. Many of us are beginning to carry multiple mobile devices and we seek to re-evaluate the traditional view of a mobile device as only accepting energy. In our vision, we can...... sharing futures....

  1. CONCEPT OF MOBILE LEARNING

    Directory of Open Access Journals (Sweden)

    Г О Дуйсеева

    2016-12-01

    Full Text Available This article deals with the definition and the description of mobile learning. Ten years’ experience of the latest mobile technologies use and devices in educational process abroad is analyzed. Prospects and the possibilities of application of these technologies are considered. The basic concepts and development of mobile learning which proposed by scientists for the last years have been given.

  2. Marketing mobile imaging services.

    Science.gov (United States)

    McCue, P

    1987-09-01

    Competition in the mobile imaging arena has put radiologists, radiology directors, and other health care professionals in the unfamiliar position of being marketing agents for their services. Mobile imaging is being promoted through consumer advertising as well as through the traditional route of physician referral. This article offers some of the marketing lessons being learned in the mobile arena.

  3. Mobile Student Information System

    Science.gov (United States)

    Asif, Muhammad; Krogstie, John

    2011-01-01

    Purpose: A mobile student information system (MSIS) based on mobile computing and context-aware application concepts can provide more user-centric information services to students. The purpose of this paper is to describe a system for providing relevant information to students on a mobile platform. Design/methodology/approach: The research…

  4. Extracting hot carriers from photoexcited semiconductor nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Xiaoyang

    2014-12-10

    This research program addresses a fundamental question related to the use of nanomaterials in solar energy -- namely, whether semiconductor nanocrystals (NCs) can help surpass the efficiency limits, the so-called “Shockley-Queisser” limit, in conventional solar cells. In these cells, absorption of photons with energies above the semiconductor bandgap generates “hot” charge carriers that quickly “cool” to the band edges before they can be utilized to do work; this sets the solar cell efficiency at a limit of ~31%. If instead, all of the energy of the hot carriers could be captured, solar-to-electric power conversion efficiencies could be increased, theoretically, to as high as 66%. A potential route to capture this energy is to utilize semiconductor nanocrystals. In these materials, the quasi-continuous conduction and valence bands of the bulk semiconductor become discretized due to confinement of the charge carriers. Consequently, the energy spacing between the electronic levels can be much larger than the highest phonon frequency of the lattice, creating a “phonon bottleneck” wherein hot-carrier relaxation is possible via slower multiphonon emission. For example, hot-electron lifetimes as long as ~1 ns have been observed in NCs grown by molecular beam epitaxy. In colloidal NCs, long lifetimes have been demonstrated through careful design of the nanocrystal interfaces. Due to their ability to slow electronic relaxation, semiconductor NCs can in principle enable extraction of hot carriers before they cool to the band edges, leading to more efficient solar cells.

  5. Carbon: Hydrogen carrier or disappearing skeleton?

    International Nuclear Information System (INIS)

    De Jong, K.P.; Van Wechem, H.M.H.

    1994-01-01

    The use of liquid hydrocarbons as energy carriers implies the use of carbon as a carrier for hydrogen to facilitate hydrogen transport and storage. The current trend for liquid energy carriers used in the transport sector is to maximize the load of hydrogen on the carbon carrier. The recently developed Shell Middle Distillate Hydrogenation process for the manufacture of high quality diesel from aromatic refinery streams fits this picture. In the future, the hydrogen required to raise the product H/C ratio will be increasingly produced via gasification of large amounts of heavy residues. In the light of the strong preference towards using liquid fuels in the transport sector, the Shell Middle Distillate Synthesis process to convert natural gas into diesel of very high quality is discussed. Finally, a few comments on the use of hydrogen without a carbon carrier are made. Long lead times and the likelihood of producing the 'first' hydrogen from fossil fuel are highlighted. 13 figs., 6 tabs., 5 refs

  6. Estimating Motor Carrier Management Information System Crash File Underreporting from Carrier Records.

    Science.gov (United States)

    2017-08-01

    This FMCSA-sponsored research investigated the claim that motor carriers have a substantial number of crashes in their own records that are not contained in the Motor Carrier Management Information System (MCMIS) crash file. Based on the results of t...

  7. Estimating motor carrier management information system crash file underreporting from carrier records : research brief.

    Science.gov (United States)

    2017-08-01

    This study estimated a significant amount of underreporting to the MCMIS crash file by the States, for the carriers who cooperated in the study. For the study carriers, it appears that the MCMIS file contained about 66 percent of their reportable cra...

  8. Distributed mobility management - framework & analysis

    NARCIS (Netherlands)

    Liebsch, M.; Seite, P.; Karagiannis, Georgios

    2013-01-01

    Mobile operators consider the distribution of mobility anchors to enable offloading some traffic from their core network. The Distributed Mobility Management (DMM) Working Group is investigating the impact of decentralized mobility management to existing protocol solutions, while taking into account

  9. Spatial variation in carrier dynamics along a single CdSSe nanowire

    International Nuclear Information System (INIS)

    Blake, Jolie C.; Eldridge, Peter S.; Gundlach, Lars

    2014-01-01

    Highlights: • Femtosecond Kerr-gate microscopy allows ultrafast fluorescence measurements along different positions of a single nanowire. • Amplified spontaneous emission observed at high fluences can be used to calculate recombination rates. • Observation of ASE at different locations along a single CdSSe nanowire provides the ability to extract defect densities. - Abstract: Ultrafast charge carrier dynamics along individual CdS x Se 1−x nanowires has been measured. The use of an improved ultrafast Kerr-gated microscope allows for spatially resolved luminescence measurements along a single nanowire. Amplified spontaneous emission (ASE) was observed at high excitation fluences. Position dependent variations of ultrafast ASE dynamics were observed. SEM and colorimetric measurements showed that the difference in dynamics can be attributed to variations in non-radiative recombination rates along the wire. The dominant Shockley-Read recombination rate can be extracted from ASE dynamics and can be directly related to charge carrier mobility and defect density. Employing ASE as a probe for defect densities provides a new sub-micron spatially resolved, contactless method for measurements of charge carrier mobility

  10. Carrier Transport Enhancement in Conjugated Polymers through Interfacial Self-Assembly of Solution-State Aggregates

    KAUST Repository

    Zhao, Kui

    2016-07-13

    We demonstrate that local and long range orders of poly(3-hexylthiophene) (P3HT) semicrystalline films can be synergistically improved by combining chemical functionalization of the dielectric surface with solution-state disentanglement and pre-aggregation of P3HT in a theta solvent, leading to a very significant enhancement of the field effect carrier mobility. The pre-aggregation and surface functionalization effects combine to enhance the carrier mobility nearly 100-fold as compared with standard film preparation by spin-coating, and nearly 10-fold increase over the benefits of pre-aggregation alone. In situ quartz crystal microbalance with dissipation (QCM-D) experiments reveal enhanced deposition of pre-aggregates on surfaces modified with an alkyl-terminated self-assembled monolayer (SAM) in comparison to un-aggregated polymer chains. Additional investigations reveal the combined pre-aggregation and surface functionalization significantly enhances local order of the conjugated polymer through planarization and extension of the conjugated backbone of the polymer which clearly translate to significant improvements of carrier transport at the semiconductor-dielectric interface in organic thin film transistors. This study points to opportunities in combining complementary routes, such as well-known pre-aggregation with substrate chemical functionalization, to enhance the polymer self-assembly and improve its interfacial order with benefits for transport properties.

  11. Low-voltage and high-efficiency white organic light emitting devices with carrier balance

    International Nuclear Information System (INIS)

    Wei Fuxiang; Huang, Y.; Fang, L.

    2010-01-01

    White organic light emitting devices with the structure of ITO/m-MTDATA:x%4F-TCNQ/NPB/TBADN:EBDP:DCJTB/Bphen:Liq/LiF/Al have been demonstrated in this paper. High-mobility m-MTDATA:4F-TCNQ is added into the region between ITO and NBP to increase hole injection and transport. The high-mobility Bphen:Liq layer is added into the region between cathode and emission layers to lower cathode barrier and facilitate carrier injection. In the meanwhile, an effective carrier balance (number of holes is equal to number of electrons) between holes and electrons is considered to be one of the most important factors for improving OLEDs. During the experiment, by modulating the doping concentration of 4F-TCNQ, we can control hole injection and transport to make the carriers reach a high-level balance. The maximum current efficiency and power efficiency of devices were 9.3 cd/A and 4.6 lm/A, respectively.

  12. The influence of surfaces on the transient terahertz conductivity and electron mobility of GaAs nanowires

    International Nuclear Information System (INIS)

    Joyce, Hannah J; Baig, Sarwat A; Parkinson, Patrick; Davies, Christopher L; Boland, Jessica L; Herz, Laura M; Johnston, Michael B; Tan, H Hoe; Jagadish, Chennupati

    2017-01-01

    Bare unpassivated GaAs nanowires feature relatively high electron mobilities (400–2100 cm 2 V −1 s −1 ) and ultrashort charge carrier lifetimes (1–5 ps) at room temperature. These two properties are highly desirable for high speed optoelectronic devices, including photoreceivers, modulators and switches operating at microwave and terahertz frequencies. When engineering these GaAs nanowire-based devices, it is important to have a quantitative understanding of how the charge carrier mobility and lifetime can be tuned. Here we use optical-pump–terahertz-probe spectroscopy to quantify how mobility and lifetime depend on the nanowire surfaces and on carrier density in unpassivated GaAs nanowires. We also present two alternative frameworks for the analysis of nanowire photoconductivity: one based on plasmon resonance and the other based on Maxwell–Garnett effective medium theory with the nanowires modelled as prolate ellipsoids. We find the electron mobility decreases significantly with decreasing nanowire diameter, as charge carriers experience increased scattering at nanowire surfaces. Reducing the diameter from 50 nm to 30 nm degrades the electron mobility by up to 47%. Photoconductivity dynamics were dominated by trapping at saturable states existing at the nanowire surface, and the trapping rate was highest for the nanowires of narrowest diameter. The maximum surface recombination velocity, which occurs in the limit of all traps being empty, was calculated as 1.3  ×  10 6 cm s −1 . We note that when selecting the optimum nanowire diameter for an ultrafast device, there is a trade-off between achieving a short lifetime and a high carrier mobility. To achieve high speed GaAs nanowire devices featuring the highest charge carrier mobilities and shortest lifetimes, we recommend operating the devices at low charge carrier densities. (paper)

  13. Impact of optical phonon scattering on inversion channel mobility in 4H-SiC trenched MOSFETs

    Science.gov (United States)

    Kutsuki, Katsuhiro; Kawaji, Sachiko; Watanabe, Yukihiko; Onishi, Toru; Fujiwara, Hirokazu; Yamamoto, Kensaku; Yamamoto, Toshimasa

    2017-04-01

    Temperature characteristics of the channel mobility were investigated for 4H-SiC trenched MOSFETs in the range from 30 to 200 °C. The conventional model of channel mobility limited by carrier scattering is based on Si-MOSFETs and shows a greatly different channel mobility from the experimental value, especially at high temperatures. On the other hand, our improved mobility model taking into account optical phonon scattering yielded results in excellent agreement with experimental results. Moreover, the major factors limiting the channel mobility were found to be Coulomb scattering in a low effective field (<0.7 MV/cm) and optical phonon scattering in a high effective field.

  14. Understanding pastoral mobility

    DEFF Research Database (Denmark)

    Adriansen, Hanne Kirstine

    2008-01-01

    Based on a case study from Sahelian Senegal, this paper analyses how various actors perceive the importance of pastoral mobility and presents issues of importance for understanding the use of mobility among Fulani of Ferlo. One knowledge system is a scientific one, the 'new rangeland paradigm...... territory, which they consider their place, but are unwilling to employ large-scale mobility themselves. Mobility is not of importance for their ethnic identity and some use paid herders to care for their livestock. By looking at both knowledge systems, we achieve a better understanding of pastoral mobility...

  15. Mobile Virtual Private Networking

    Science.gov (United States)

    Pulkkis, Göran; Grahn, Kaj; Mårtens, Mathias; Mattsson, Jonny

    Mobile Virtual Private Networking (VPN) solutions based on the Internet Security Protocol (IPSec), Transport Layer Security/Secure Socket Layer (SSL/TLS), Secure Shell (SSH), 3G/GPRS cellular networks, Mobile IP, and the presently experimental Host Identity Protocol (HIP) are described, compared and evaluated. Mobile VPN solutions based on HIP are recommended for future networking because of superior processing efficiency and network capacity demand features. Mobile VPN implementation issues associated with the IP protocol versions IPv4 and IPv6 are also evaluated. Mobile VPN implementation experiences are presented and discussed.

  16. European mobility cultures

    DEFF Research Database (Denmark)

    Haustein, Sonja; Nielsen, Thomas A. Sick

    2016-01-01

    More targeted European policies promoting green travel patterns require better knowledge on differing mobility cultures across European regions. As a basis for this, we clustered the EU population into eight mobility styles based on Eurobarometer data. The mobility styles - including, for example...... positions on the path towards sustainable mobility and therefore different requirements towards European platforms and support measures, e.g. for 'Sustainable Urban Mobility Plans'. The country clusters can provide a starting point for future communication and targeting of European efforts in sustainable...

  17. Protection switching for carrier ethernet multicast

    DEFF Research Database (Denmark)

    Ruepp, Sarah Renée; Wessing, Henrik; Berger, Michael Stübert

    2010-01-01

    This paper addresses network survivability for IPTV multicast transport in Carrier Ethernet networks. The impact of link failures is investigated and suggestions for intelligent multicast resilience schemes are proposed. In particular, functions of the multicast tree are integrated with the Carri...... recovery path length, recovery time, number of branch nodes and operational complexity. The integrated approach therefore shows significant potential to increase the QoE for IPTV users in case of network failures and recovery actions.......This paper addresses network survivability for IPTV multicast transport in Carrier Ethernet networks. The impact of link failures is investigated and suggestions for intelligent multicast resilience schemes are proposed. In particular, functions of the multicast tree are integrated with the Carrier...

  18. Natural carriers in bioremediation: A review

    Directory of Open Access Journals (Sweden)

    Anna Dzionek

    2016-09-01

    Full Text Available Bioremediation of contaminated groundwater or soil is currently the cheapest and the least harmful method of removing xenobiotics from the environment. Immobilization of microorganisms capable of degrading specific contaminants significantly promotes bioremediation processes, reduces their costs, and also allows for the multiple use of biocatalysts. Among the developed methods of immobilization, adsorption on the surface is the most common method in bioremediation, due to the simplicity of the procedure and its non-toxicity. The choice of carrier is an essential element for successful bioremediation. It is also important to consider the type of process (in situ or ex situ, type of pollution, and properties of immobilized microorganisms. For these reasons, the article summarizes recent scientific reports about the use of natural carriers in bioremediation, including efficiency, the impact of the carrier on microorganisms and contamination, and the nature of the conducted research.

  19. Hiding secret data into a carrier image

    Directory of Open Access Journals (Sweden)

    Ovidiu COSMA

    2012-06-01

    Full Text Available The object of steganography is embedding hidden information in an appropriate multimedia carrier, e.g., image, audio, or video. There are several known methods of solving this problem, which operate either in the space domain or in the frequency domain, and are distinguished by the following characteristics: payload, robustness and strength. The payload is the amount of secret data that can be embedded in the carrier without inducing suspicious artefacts, robustness indicates the degree in which the secret data is affected by the normal processing of the carrier e.g., compression, and the strength indicate how easy the presence of hidden data can be detected by steganalysis techniques. This paper presents a new method of hiding secret data into a digital image compressed by a technique based on the Discrete Wavelet Transform (DWT [2] and the Set Partitioning In Hierarchical Trees (SPIHT subband coding algorithm [6]. The proposed method admits huge payloads and has considerable strength.

  20. Why is CDMA the solution for mobile satellite communication

    Science.gov (United States)

    Gilhousen, Klein S.; Jacobs, Irwin M.; Padovani, Roberto; Weaver, Lindsay A.

    1989-01-01

    It is demonstrated that spread spectrum Code Division Multiple Access (CDMA) systems provide an economically superior solution to satellite mobile communications by increasing the system maximum capacity with respect to single channel per carrier Frequency Division Multiple Access (FDMA) systems. Following the comparative analysis of CDMA and FDMA systems, the design of a model that was developed to test the feasibility of the approach and the performance of a spread spectrum system in a mobile environment. Results of extensive computer simulations as well as laboratory and field tests results are presented.

  1. Mobile Technology Waiting for the 3G Rush

    Institute of Scientific and Technical Information of China (English)

    HAYET SELLAMI

    2006-01-01

    @@ China is potentially the biggest third generation (3G) mobile market in the world, and everyone is eager to grab a piece of the pie. Foreign carriers are still not allowed to apply for licences since China's decision regarding licensing and adoption of 3G mobile services is still pending, but the waiting list is long. Both Chinese officials and industry executives have stated that they want 3G in place in time for the August 2008 Olympic Games held in Beijing. This tight deadline leaves no room for failure.

  2. Engaging with mobile methods

    DEFF Research Database (Denmark)

    Jensen, Martin Trandberg

    2014-01-01

    This chapter showcases how mobile methods are more than calibrated techniques awaiting application by tourism researchers, but productive in the enactment of the mobile (Law and Urry, 2004). Drawing upon recent findings deriving from a PhD course on mobility and mobile methods it reveals...... the conceptual ambiguousness of the term ‘mobile methods’. In order to explore this ambiguousness the chapter provides a number of examples deriving from tourism research, to explore how mobile methods are always entangled in ideologies, predispositions, conventions and practice-realities. Accordingly......, the engagements with methods are acknowledged to be always political and contextual, reminding us to avoid essentialist discussions regarding research methods. Finally, the chapter draws on recent fieldwork to extend developments in mobilities-oriented tourism research, by employing auto-ethnography to call...

  3. Mobile systems development

    DEFF Research Database (Denmark)

    Pedersen, Ole; Kristiansen, Martin Lund; Kammersgaard, Marc N.

    2007-01-01

    in XP. In general, we find XP well-suited for mobile systems development projects. However, based on our experiences and an analytical comparison we propose the following modifications to XP: Make an essential design to avoid the worst time waste during refactoring. For faster development, reuse code......Development of mobile software is Surrounded by much uncertainty. Immature software platforms on mobile clients, a highly competitive market calling for innovation, efficiency and effectiveness in the development life cycle, and lacking end-user adoption are just some of the realities facing...... development teams in the mobile software industry. By taking a process view on development of mobile systems we seek to explore the strengths and limitations of eXtreme Programming (XP) in the context of mobile software development. Following an experimental approach a mobile systems development project...

  4. Towards 100 gigabit carrier ethernet transport networks

    DEFF Research Database (Denmark)

    Rasmussen, Anders; Zhang, Jiang; Yu, Hao

    2010-01-01

    technology, making the use of Ethernet as a convergence layer for Next Generation Networks a distinct possibility. Triple Play services, in particular IPTV, are expected to be a main drivers for carrier Ethernet, however, a number of challenges must be addressed including QoS enabled control plane, enhanced......Ethernet as a transport technology has, up to now, lacked the features such as network layer architecture, customer separation and manageability that carriers require for wide-scale deployment. However, with the advent of PBB-TE and TMPLS, it is now possible to use Ethernet as a transport...

  5. Interface recombination influence on carrier transport

    International Nuclear Information System (INIS)

    Konin, A

    2013-01-01

    A theory of interface recombination in the semiconductor–semiconductor junction is developed. The interface recombination rate dependence on the nonequilibrium carrier densities is derived on the basis of a model in which the interface recombination occurs through the mechanism of trapping. The general relation between the interface recombination parameters at small carrier density deviation from the equilibrium ones is obtained. The validity of this relation is proved considering the generation of the Hall electric field in the extrinsic semiconductor sample. The anomalous Hall electromotive force in a weak magnetic field was investigated and interpreted by means of a new interface recombination model. The experimental data corroborate the developed theory. (paper)

  6. Hot-carrier effects in MOS devices

    CERN Document Server

    Takeda, Eiji; Miura-Hamada, Akemi

    1995-01-01

    The exploding number of uses for ultrafast, ultrasmall integrated circuits has increased the importance of hot-carrier effects in manufacturing as well as for other technological applications. They are rapidly movingout of the research lab and into the real world.This book is derived from Dr. Takedas book in Japanese, Hot-Carrier Effects, (published in 1987 by Nikkei Business Publishers). However, the new book is much more than a translation. Takedas original work was a starting point for developing this much more complete and fundamental text on this increasingly important topic. The new work

  7. The effect of Coulomb interactions on the ac mobility of charges in quasi-one-dimensional systems. Example : Discotic liquid crystals

    NARCIS (Netherlands)

    Siebbeles, L.D.A.; Movaghar, B.

    2000-01-01

    Using Monte Carlo simulations we calculate the frequency dependence of the diffusive mobility of a group of carriers on a short one-dimensional chain. We allow the carriers to interact with each other through weakly screened long-range Coulomb potentials. We consider both doped systems with discrete

  8. Connecting Mobile Users Through Mobile Social Networks

    Directory of Open Access Journals (Sweden)

    Faisal Alkhateeb

    2012-10-01

    Full Text Available Nowadays, social networks become popular with the emerging of web-based social networking services. Recently, several mobile services are developed to connect users to their favourite social networks such as Facebook, Twitter, Flickr, etc. However, these services depends upon the existing web-based social networks. In this paper, we present a mobile service for joining groups across communities. The originality of the work is that the framework of the service allows creating and joining social networks that are self-contained for mobile company servers. The service consists of several sub-services such as users invitation, group finding and others. Users, regardless of their disability, can use the service and its sub-services without the need to create their own accounts on social web sites and thus their own groups. We also propose a privacy control policy for mobile social networks.

  9. Non-monotonic effect of growth temperature on carrier collection in SnS solar cells

    International Nuclear Information System (INIS)

    Chakraborty, R.; Steinmann, V.; Mangan, N. M.; Brandt, R. E.; Poindexter, J. R.; Jaramillo, R.; Mailoa, J. P.; Hartman, K.; Polizzotti, A.; Buonassisi, T.; Yang, C.; Gordon, R. G.

    2015-01-01

    We quantify the effects of growth temperature on material and device properties of thermally evaporated SnS thin-films and test structures. Grain size, Hall mobility, and majority-carrier concentration monotonically increase with growth temperature. However, the charge collection as measured by the long-wavelength contribution to short-circuit current exhibits a non-monotonic behavior: the collection decreases with increased growth temperature from 150 °C to 240 °C and then recovers at 285 °C. Fits to the experimental internal quantum efficiency using an opto-electronic model indicate that the non-monotonic behavior of charge-carrier collection can be explained by a transition from drift- to diffusion-assisted components of carrier collection. The results show a promising increase in the extracted minority-carrier diffusion length at the highest growth temperature of 285 °C. These findings illustrate how coupled mechanisms can affect early stage device development, highlighting the critical role of direct materials property measurements and simulation

  10. Current fluctuation of electron and hole carriers in multilayer WSe{sub 2} field effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Seung-Pil; Shin, Jong Mok; Jang, Ho-Kyun; Jin, Jun Eon; Kim, Gyu-Tae, E-mail: gtkim@korea.ac.kr [School of Electrical Engineering, Korea University, Seoul 02481 (Korea, Republic of); Kim, Yong Jin; Kim, Young Keun [Department of Materials Science and Engineering, Korea University, Seoul 02481 (Korea, Republic of); Shin, Minju [School of Electrical Engineering, Korea University, Seoul 02481 (Korea, Republic of); IMEP-LAHC, Grenoble INP-MINATEC, 3 Parvis Louis Neel, 38016 Grenoble (France)

    2015-12-14

    Two-dimensional materials have outstanding scalability due to their structural and electrical properties for the logic devices. Here, we report the current fluctuation in multilayer WSe{sub 2} field effect transistors (FETs). In order to demonstrate the impact on carrier types, n-type and p-type WSe{sub 2} FETs are fabricated with different work function metals. Each device has similar electrical characteristics except for the threshold voltage. In the low frequency noise analysis, drain current power spectral density (S{sub I}) is inversely proportional to frequency, indicating typical 1/f noise behaviors. The curves of the normalized drain current power spectral density (NS{sub I}) as a function of drain current at the 10 Hz of frequency indicate that our devices follow the carrier number fluctuation with correlated mobility fluctuation model. This means that current fluctuation depends on the trapping-detrapping motion of the charge carriers near the channel interface. No significant difference is observed in the current fluctuation according to the charge carrier type, electrons and holes that occurred in the junction and channel region.

  11. Seasonal storage and alternative carriers: A flexible hydrogen supply chain model

    International Nuclear Information System (INIS)

    Reuß, M.; Grube, T.; Robinius, M.; Preuster, P.; Wasserscheid, P.; Stolten, D.

    2017-01-01

    Highlights: •Techno-economic model of future hydrogen supply chains. •Implementation of liquid organic hydrogen carriers into a hydrogen mobility analysis. •Consideration of large-scale seasonal storage for fluctuating renewable hydrogen production. •Implementation of different technologies for hydrogen storage and transportation. -- Abstract: A viable hydrogen infrastructure is one of the main challenges for fuel cells in mobile applications. Several studies have investigated the most cost-efficient hydrogen supply chain structure, with a focus on hydrogen transportation. However, supply chain models based on hydrogen produced by electrolysis require additional seasonal hydrogen storage capacity to close the gap between fluctuation in renewable generation from surplus electricity and fuelling station demand. To address this issue, we developed a model that draws on and extends approaches in the literature with respect to long-term storage. Thus, we analyse Liquid Organic Hydrogen Carriers (LOHC) and show their potential impact on future hydrogen mobility. We demonstrate that LOHC-based pathways are highly promising especially for smaller-scale hydrogen demand and if storage in salt caverns remains uncompetitive, but emit more greenhouse gases (GHG) than other gaseous or hydrogen ones. Liquid hydrogen as a seasonal storage medium offers no advantage compared to LOHC or cavern storage since lower electricity prices for flexible operation cannot balance the investment costs of liquefaction plants. A well-to-wheel analysis indicates that all investigated pathways have less than 30% GHG-emissions compared to conventional fossil fuel pathways within a European framework.

  12. Carbon doped GaAs/AlGaAs heterostructures with high mobility two dimensional hole gas

    Energy Technology Data Exchange (ETDEWEB)

    Hirmer, Marika; Bougeard, Dominique; Schuh, Dieter [Institut fuer Experimentelle und Angewandte Physik, Universitaet Regensburg, D 93040 Regensburg (Germany); Wegscheider, Werner [Laboratorium fuer Festkoerperphysik, ETH Zuerich, 8093 Zuerich (Switzerland)

    2011-07-01

    Two dimensional hole gases (2DHG) with high carrier mobilities are required for both fundamental research and possible future ultrafast spintronic devices. Here, two different types of GaAs/AlGaAs heterostructures hosting a 2DHG were investigated. The first structure is a GaAs QW embedded in AlGaAs barrier grown by molecular beam epitaxy with carbon-doping only at one side of the quantum well (QW) (single side doped, ssd), while the second structure is similar but with symmetrically arranged doping layers on both sides of the QW (double side doped, dsd). The ssd-structure shows hole mobilities up to 1.2*10{sup 6} cm{sup 2}/Vs which are achieved after illumination. In contrast, the dsd-structure hosts a 2DHG with mobility up to 2.05*10{sup 6} cm{sup 2}/Vs. Here, carrier mobility and carrier density is not affected by illuminating the sample. Both samples showed distinct Shubnikov-de-Haas oscillations and fractional quantum-Hall-plateaus in magnetotransport experiments done at 20mK, indicating the high quality of the material. In addition, the influence of different temperature profiles during growth and the influence of the Al content of the barrier Al{sub x}Ga{sub 1-x}As on carrier concentration and mobility were investigated and are presented here.

  13. Wireless Emergency Alerts Commercial Mobile Service Provider (CMSP) Cybersecurity Guidelines

    Science.gov (United States)

    2016-06-16

    Switching Centers (MSCs) in CDMA networks . The interface standard be- tween the MC and CDMA networks is the IS-824, IS-637 SMDPP.  Global System for... networks is 3GPP 23.041 CBS-BSC.  Universal Mobile Telecommunications System (UMTS) networks : A CBC function is collocated with a CMSP Gateway for message...agement 16. Does the carrier patch all systems and network devices as appropriate?    CMU/SEI-2016-SR-009 | SOFTWARE ENGINEERING INSTITUTE

  14. 33 CFR 165.835 - Security Zone; Port of Mobile, Mobile Ship Channel, Mobile, AL.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Security Zone; Port of Mobile, Mobile Ship Channel, Mobile, AL. 165.835 Section 165.835 Navigation and Navigable Waters COAST GUARD... § 165.835 Security Zone; Port of Mobile, Mobile Ship Channel, Mobile, AL. (a) Definition. As used in...

  15. Carrier of Wingless (Cow), a Secreted Heparan Sulfate Proteoglycan, Promotes Extracellular Transport of Wingless

    Science.gov (United States)

    Chang, Yung-Heng; Sun, Yi Henry

    2014-01-01

    Morphogens are signaling molecules that regulate growth and patterning during development by forming a gradient and activating different target genes at different concentrations. The extracellular distribution of morphogens is tightly regulated, with the Drosophila morphogen Wingless (Wg) relying on Dally-like (Dlp) and transcytosis for its distribution. However, in the absence of Dlp or endocytic activity, Wg can still move across cells along the apical (Ap) surface. We identified a novel secreted heparan sulfate proteoglycan (HSPG) that binds to Wg and promotes its extracellular distribution by increasing Wg mobility, which was thus named Carrier of Wg (Cow). Cow promotes the Ap transport of Wg, independent of Dlp and endocytosis, and this function addresses a previous gap in the understanding of Wg movement. This is the first example of a diffusible HSPG acting as a carrier to promote the extracellular movement of a morphogen. PMID:25360738

  16. Low intrinsic carrier density LSMO/Alq3/AlOx/Co organic spintronic devices

    Science.gov (United States)

    Riminucci, Alberto; Graziosi, Patrizio; Calbucci, Marco; Cecchini, Raimondo; Prezioso, Mirko; Borgatti, Francesco; Bergenti, Ilaria; Dediu, Valentin Alek

    2018-04-01

    The understanding of spin injection and transport in organic spintronic devices is still incomplete, with some experiments showing magnetoresistance and others not detecting it. We have investigated the transport properties of a large number of tris-(8-hydroxyquinoline)aluminum-based organic spintronic devices with an electrical resistance greater than 5 MΩ that did not show magnetoresistance. Their transport properties could be described satisfactorily by known models for organic semiconductors. At high voltages (>2 V), the results followed the model of space charge limited current with a Poole-Frenkel mobility. At low voltages (˜0.1 V), that are those at which the spin valve behavior is usually observed, the charge transport was modelled by nearest neighbor hopping in intra-gap impurity levels, with a charge carrier density of n0 = (1.44 ± 0.21) × 1015 cm-3 at room temperature. Such a low carrier density can explain why no magnetoresistance was observed.

  17. Influence of Inter Carrier Interference on Link Adaptation Algorithms in OFDM Systems

    DEFF Research Database (Denmark)

    Das, Suvra S.; Rahman, Muhammad Imadur; Wang, Yuanye

    2007-01-01

    The performance of Link Adaptation (LA) under the influence of inter carrier interference (ICI), which is cause by carrier frequency offset (CFO) and Doppler frequency spread due to mobility, in orthogonal frequency division multiplexing (OFDM) based wireless systems is analyzed in this work. LA...... maximizes throughput while maintaining a target bit error rate (BER)or Block Error Rate (BLER) at the receiver using the signal to noise ratio (SNR) fed back from the receiver to the transmitter. Since ICI power is proportional to the signal strength, the implications of such an impairment on LA OFDM...... can over the problem. It is also noted that ICI severely reduces the spectral efficiency of OFDM systems even when LA is used....

  18. Hall mobility reduction in single-crystalline silicon gradually compensated by thermal donors activation

    Science.gov (United States)

    Veirman, J.; Dubois, S.; Enjalbert, N.; Garandet, J. P.; Heslinga, D. R.; Lemiti, M.

    2010-06-01

    This letter focuses on the variation of the Hall majority carrier mobility with the dopant compensation level in purely Boron-doped Czochralski grown silicon single crystals. Compensation was varied continuously at the sample scale via a step by step activation of the oxygen-based thermal donors. At room temperature, we show a strong drop in mobility for high compensation levels in both p- and n-type Si. Mobility models taking into account carrier scattering on ionized impurities and phonons could not reproduce this drop. We conclude that a specific effect of compensation must be taken into account to explain the observed behaviour. We qualitatively discuss physical mechanisms susceptible to reduce mobility in highly compensated Si.

  19. Rational In Silico Design of an Organic Semiconductor with Improved Electron Mobility.

    Science.gov (United States)

    Friederich, Pascal; Gómez, Verónica; Sprau, Christian; Meded, Velimir; Strunk, Timo; Jenne, Michael; Magri, Andrea; Symalla, Franz; Colsmann, Alexander; Ruben, Mario; Wenzel, Wolfgang

    2017-11-01

    Organic semiconductors find a wide range of applications, such as in organic light emitting diodes, organic solar cells, and organic field effect transistors. One of their most striking disadvantages in comparison to crystalline inorganic semiconductors is their low charge-carrier mobility, which manifests itself in major device constraints such as limited photoactive layer thicknesses. Trial-and-error attempts to increase charge-carrier mobility are impeded by the complex interplay of the molecular and electronic structure of the material with its morphology. Here, the viability of a multiscale simulation approach to rationally design materials with improved electron mobility is demonstrated. Starting from one of the most widely used electron conducting materials (Alq 3 ), novel organic semiconductors with tailored electronic properties are designed for which an improvement of the electron mobility by three orders of magnitude is predicted and experimentally confirmed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Mobile Phone Penetration, Mobile Banking and Inclusive Development in Africa

    OpenAIRE

    Asongu, Simplice; Nwachukwu, Jacinta C.

    2016-01-01

    The study assesses the role of mobile phones and mobile banking in decreasing inequality in 52 African countries. The empirical procedure involves first, examining the income-redistributive effect of mobile phone penetration and then investigating the contribution of mobile banking services in this relationship. The findings suggest an equalizing income-redistributive effect of ‘mobile phone penetration’ and ‘mobile banking’, with a higher income-equalizing effect from mobile banking compared...

  1. Carrier portfolio management for shipping seasonal products

    NARCIS (Netherlands)

    Lu, T.; Fransoo, J.C.; Lee, C.-Y.

    2017-01-01

    Many seasonal products are transported via ocean carriers from origin to destination markets. The shipments arriving earlier in the market may sell at higher prices, but faster shipping services can be costly. In this paper, we study a newsvendor-type shipper who transports and sells seasonal

  2. OCP: Opportunistic Carrier Prediction for Wireless Networks

    Science.gov (United States)

    2008-08-01

    Many protocols have been proposed for medium access control in wireless networks. MACA [13], MACAW [3], and FAMA [8] are the earlier proposals for...world performance of carrier sense. In Proceedings of ACM SIGCOMM E-WIND Workshop, 2005. [13] P. Karn. MACA : A new channel access method for packet radio

  3. A new lubricant carrier for metal forming

    DEFF Research Database (Denmark)

    Arentoft, Mogens; Bay, Niels; Tang, Peter Torben

    2009-01-01

    A lubricant carrier for metal forming processes is developed. Surfaces with pores of micrometer size for entrapping lubricant are generated by electrochemical deposition of an alloy, consisting of two immiscible metals, of which one metal subsequently is etched away leaving 5 mu m layers with a s...... extrusion at high reduction and excessive stroke comparing with conventionally lubrication using phosphate coating and soap....

  4. Probing ultrafast carrier dynamics, nonlinear absorption

    Indian Academy of Sciences (India)

    We investigate the relaxation dynamics of photogenerated carriers in silicon nanowires consisting of a crystalline core and a surrounding amorphous shell, using femtosecond time resolved differential reflectivity and transmission spectroscopy at 3.15 eV and 1.57 eV photon energies. The complex behaviour of the ...

  5. European regulatory framework for person carrier robots

    NARCIS (Netherlands)

    Fosch Villaronga, E.; Roig, A.

    The aim of this paper is to establish the grounds for a future regulatory framework for Person Carrier Robots, which includes legal and ethical aspects. Current industrial standards focus on physical human–robot interaction, i.e. on the prevention of harm. Current robot technology nonetheless

  6. On safety of radioactive waste carrier

    International Nuclear Information System (INIS)

    Kondo, Toshikazu

    1995-01-01

    The waste generated by reprocessing the spent fuel from Japanese nuclear power stations in France and U.K. is to be returned to Japan. The first return transport was carried out from February to April when the waste management facility in Rokkasho, Aomori Prefecture, was completed. Most of this return transport was the sea transport using the exclusively used carrier, Pacific Pintail, from Cherbourg, France, to Mutsu Ogawara, Japan. Ministry of Transport carried out the examination on the safety of this method of transport including the safety of the carrier based on the rule for the sea transport and storage of dangerous substances. The international rule on the sea transport of high level radioactive waste, the course of adopting the INF code and its outline, and the Japanese safety standard for the carriers exclusively used for high level radioactive waste are explained. The Pacific Pintail is the ship of 5087 GT, which was built in 1987 as the carrier exclusively used for radioactive substances, owned by Pacific Nuclear Transport Ltd. of U.K. The main features related to the safety of the Pacific Pintail are explained, and the sufficient countermeasures are taken. (K.I.)

  7. Quantitative evaluation of spatial scale of carrier trapping at grain boundary by GHz-microwave dielectric loss spectroscopy

    Science.gov (United States)

    Choi, W.; Tsutsui, Y.; Miyakai, T.; Sakurai, T.; Seki, S.

    2017-11-01

    Charge carrier mobility is an important primary parameter for the electronic conductive materials, and the intrinsic limit of the mobility has been hardly access by conventional direct-current evaluation methods. In the present study, intra-grain hole mobility of pentacene thin films was estimated quantitatively using microwave-based dielectric loss spectroscopy (time-resolved microwave conductivity measurement) in alternating current mode of charge carrier local motion. Metal-insulator-semiconductor devices were prepared with different insulating polymers or substrate temperature upon vacuum deposition of the pentacene layer, which afforded totally four different grain-size conditions of pentacene layers. Under the condition where the local motion was determined by interfacial traps at the pentacene grain boundaries (grain-grain interfaces), the observed hole mobilities were plotted against the grain sizes, giving an excellent correlation fit successfully by a parabolic function representative of the boarder length. Consequently, the intra-grain mobility and trap-release time of holes were estimated as 15 cm2 V-1 s-1 and 9.4 ps.

  8. Cosmogenic radionuclide carriers in the atmosphere

    International Nuclear Information System (INIS)

    Lujaniene, G.; Lujanas, V.

    1998-01-01

    The investigation of radionuclides ( 7 Be 32,33 P and 35 S) and stable sulfur and phosphorus forms was based on the Tessier sequential extraction method. The properties of radionuclide carriers can be transformed in the atmosphere in a very short time (days, hours), in contrast to soil and the hydrosphere. Oxidation processes proceeding in the atmosphere induce changes in the aerosol carrier properties. The aerosol can be characterized by low pH and high Eh values corresponding to high 7Be solubility. The unexpectedly high negative Eh values obtained in dry summer period indicate that the 7 Be 32,33 P aerosol is bound to insoluble carriers. 137 Cs solubility does not depend on changes in pH. This can be explained by the fact that in contrast to 7 Be, 137 Cs is associated with the exchangeable fraction. Cs ions can be replaced not only by H + but also by NH 4 + and other ions. 7 Be aerosols collected at the seaside of the Baltic sea (Preila) were found to be more soluble than those in Vilnius, their solubility was up to 50-90 % and clear dependence between 7 Be solubility, pH and Eh was not observed. It can be attributed to differences in the atmospheric aerosol composition (e.g. soluble chlorides) in Vilnius and Preila. A great variety of 7 Be carriers properties as well as their dependence on the season and the existence of admixtures in the atmosphere require great caution in applying this isotope in tracer investigations. Soluble carriers are removed faster from the atmosphere by precipitation. The significance of this fact is confirmed by the ratio of 7 Be/ 32 P in the air and precipitation. Both soluble and insoluble aerosols can be formed depending on the environmental conditions

  9. Limitations of high dose carrier based formulations.

    Science.gov (United States)

    Yeung, Stewart; Traini, Daniela; Tweedie, Alan; Lewis, David; Church, Tanya; Young, Paul M

    2018-06-10

    This study was performed to investigate how increasing the active pharmaceutical ingredient (API) content within a formulation affects the dispersion of particles and the aerosol performance efficiency of a carrier based dry powder inhalable (DPI) formulation, using a custom dry powder inhaler (DPI) development rig. Five formulations with varying concentrations of API beclomethasone dipropionate (BDP) between 1% and 30% (w/w) were formulated as a multi-component carrier system containing coarse lactose and fine lactose with magnesium stearate. The morphology of the formulation and each component were investigated using scanning electron micrographs while the particle size was measured by laser diffraction. The aerosol performance, in terms of aerodynamic diameter, was assessed using the British pharmacopeia Apparatus E cascade impactor (Next generation impactor). Chemical analysis of the API was observed by high performance liquid chromatography (HPLC). Increasing the concentration of BDP in the blend resulted in increasing numbers and size of individual agglomerates and densely packed BDP multi-layers on the surface of the lactose carrier. BDP present within the multi-layer did not disperse as individual primary particles but as dense agglomerates, which led to a decrease in aerosol performance and increased percentage of BDP deposition within the Apparatus E induction port and pre-separator. As the BDP concentration in the blends increases, aerosol performance of the formulation decreases, in an inversely proportional manner. Concurrently, the percentage of API deposition in the induction port and pre-separator could also be linked to the amount of micronized particles (BDP and Micronized composite carrier) present in the formulation. The effect of such dose increase on the behaviour of aerosol dispersion was investigated to gain greater insight in the development and optimisation of higher dosed carrier-based formulations. Copyright © 2018 Elsevier B.V. All

  10. Compact modeling of nanoscale triple-gate junctionless transistors covering drift-diffusion to quasi-ballistic carrier transport

    Science.gov (United States)

    Oproglidis, T. A.; Karatsori, T. A.; Barraud, S.; Ghibaudo, G.; Dimitriadis, C. A.

    2018-04-01

    In this work, we extend our analytical compact model for nanoscale junctionless triple-gate (JL TG) MOSFETs, capturing carrier transport from drift-diffusion to quasi-ballistic regime. This is based on a simple formulation of the low-field mobility extracted from experimental data using the Y-function method, taking into account the ballistic carrier motion and an increased carrier scattering in process-induced defects near the source/drain regions. The case of a Schottky junction in non-ideal ohmic contact at the drain side was also taken into account by modifying the threshold voltage and ideality factor of the JL transistor. The model is validated with experimental data for n-channel JL TG MOSFETs with channel length varying from 95 down to 25 nm. It can be easily implemented as a compact model for use in Spice circuit simulators.

  11. Revealing the ultrafast charge carrier dynamics in organo metal halide perovskite solar cell materials using time resolved THz spectroscopy

    Science.gov (United States)

    Ponseca, C. S., Jr.; Sundström, V.

    2016-03-01

    Ultrafast charge carrier dynamics in organo metal halide perovskite has been probed using time resolved terahertz (THz) spectroscopy (TRTS). Current literature on its early time characteristics is unanimous: sub-ps charge carrier generation, highly mobile charges and very slow recombination rationalizing the exceptionally high power conversion efficiency for a solution processed solar cell material. Electron injection from MAPbI3 to nanoparticles (NP) of TiO2 is found to be sub-ps while Al2O3 NPs do not alter charge dynamics. Charge transfer to organic electrodes, Spiro-OMeTAD and PCBM, is sub-ps and few hundreds of ps respectively, which is influenced by the alignment of energy bands. It is surmised that minimizing defects/trap states is key in optimizing charge carrier extraction from these materials.

  12. Making Everyday Mobility

    DEFF Research Database (Denmark)

    Wind, Simon

    2013; Urry 2007) and family theory (Holdsworth 2013; Morgan 2011), it is argued that family mobility is far from only an instrumental phenomenon, displacing family members back and forth between activities and doings, but also a type of family practice (Morgan, 2011) carrying social and emotional...... coping process in the family, it is argued that making and performing mobility practices is to be understood as creating elasticity. Following this, it is elasticity that enables family members to stretch to accommodate the family’s practical, social and emotional conditions as well as adapt......Based upon a qualitative PhD study of 11 families everyday mobility, this paper inquiries into the everyday mobility of families with children in the Greater Copenhagen Area and the role mobility plays in contributing to coping in the families’ everyday life. Drawing on Mobilities theory (Jensen...

  13. Mobilities, Futures & the City

    DEFF Research Database (Denmark)

    Freudendal-Pedersen, Malene; Kesselring, Sven

    2016-01-01

    significant attention to these shifts in societies’ discursive patterns and structures. For making up powerful and strong visions and policies for sustainable cities, ‘collaborative storytelling’ plays a key role. The theoretical outset for the research project ‘Mobilities, Futures & the City’, which grounds......The future of cities and regions will be strongly shaped by the mobilities of people, goods, modes of transport, waste and information. In many ways, the ‘why and ‘for what’ often get lost in discourses on planning and designing mobilities. The predominant planning paradigm still conceptualizes...... the future of cities and mobilities as a matter of rather more efficient technologies than of social cohesion, integration and connectivity. Sustainable mobility needs the mobilities of ideas and concepts and the reflexivity of policies. Communicative planning theory and the ‘argumentative turn’ have given...

  14. CERN Mobility Survey

    CERN Multimedia

    GS Department

    2011-01-01

    The Institute of Shipping and Transport of the University of the Aegean and the National Technical University of Athens are partners with CERN in a study of mobility patterns between and within the CERN sites and to that effect have realized a mobility survey dedicated to the CERN community.         The study aims to understand: How you presently get around the CERN sites; What problems you encounter regarding mobility; What your needs are; What improvements you’d like to see; What measures you would like to see implemented most. The replies we receive will enable us to define a general policy promoting the diversity of mobility at CERN and to establish and quantify the strategic actions to be implemented for both the short and medium term. The objectives of the transport mobility plans are to: Facilitate mobility within and between the CERN sites by identifying adequate solutions in response to individual ...

  15. Social Perspectives on Mobility

    DEFF Research Database (Denmark)

    Uth Thomsen, Thyra; Gudmundsson, Henrik; Drewes Nielsen, Lise

    Globalisation is heavily dependent on physical transport, as people and goods travel over longer distances and with higher frequency. Movement and mobility have become integrated parts of late modern identity and practice, and a state of flux can be sensed everywhere. Bringing together the latest...... interdisciplinary theoretical approaches with empirical case studies analysing and appraising innovative policies from Scandinavia, this volume demonstrates that mobility research is a key issue within social enquiry. It addresses three broad themes. Firstly, mobility as a constructed social reality, examining how...... individuals construct notions of mobility in their everyday life and practice. Secondly, mobility as spatial co-ordination and transgression, and finally, mobility as a policy theme, where the contributors explore recent developments in transport policy at national and European levels, suggesting ways forward...

  16. Embodied Cultures of Mobilities

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    2010-01-01

    and material artifacts. The paper target the complex relationship between the moving, sensing body and the material and built environment of infrastructures and mobility modes in order to explore what norms, and meanings, and everyday life mobility cultures are being produced and re-produced in this process....... A particular emphasis is put on how mobilities produce and re-produce norms, meanings and cultures in relation to the Everyday life perspective. By looking into walking, running, cycling, driving and mass transit mobilities different modes of embodied mobility is identified. The theoretical framework is based...... and interaction (Lynch). The argument is thus that understanding embodied cultures of mobilities from the vantage point of this paper lend is self to new interpretations, explorations and understandings of what it means to move within and between other social agents in particular material and physical...

  17. Quality attributes for mobile applications

    OpenAIRE

    Fernandes, João M.; Ferreira, André Leite

    2016-01-01

    A mobile application is a type of software application developed to run on a mobile device. The chapter discusses the main characteristics of mobile devices, since they have a great impact on mobile applications. It also presents the classification of mobile applications according to two main types: native and web-based applications. Finally, this chapter identifies the most relevant types of quality attributes for mobile applications. It shows that the relevant quality attributes for mobile ...

  18. Mobile wallets' business models

    OpenAIRE

    Buchinger, Uschi; Ranaivoson, Heritiana; Ballon, Pieter

    2017-01-01

    Background and Purpose: Though Mobile Wallets have the potential to entirely substitute their physical predecessor, many Mobile Wallets narrow their operations to one particular feature. This might be because of strategic business- model design choices to position themselves strategically as intermediates between users and business partners (third parties) in more delimited markets. Thus, Mobile Wallet Applications (MWAs) often represent platforms in narrow two-sided market structures. De...

  19. Mobile learning in medicine

    Science.gov (United States)

    Serkan Güllüoüǧlu, Sabri

    2013-03-01

    This paper outlines the main infrastructure for implicating mobile learning in medicine and present a sample mobile learning application for medical learning within the framework of mobile learning systems. Mobile technology is developing nowadays. In this case it will be useful to develop different learning environments using these innovations in internet based distance education. M-learning makes the most of being on location, providing immediate access, being connected, and acknowledges learning that occurs beyond formal learning settings, in places such as the workplace, home, and outdoors. Central to m-learning is the principle that it is the learner who is mobile rather than the device used to deliver m learning. The integration of mobile technologies into training has made learning more accessible and portable. Mobile technologies make it possible for a learner to have access to a computer and subsequently learning material and activities; at any time and in any place. Mobile devices can include: mobile phone, personal digital assistants (PDAs), personal digital media players (eg iPods, MP3 players), portable digital media players, portable digital multimedia players. Mobile learning (m-learning) is particularly important in medical education, and the major users of mobile devices are in the field of medicine. The contexts and environment in which learning occurs necessitates m-learning. Medical students are placed in hospital/clinical settings very early in training and require access to course information and to record and reflect on their experiences while on the move. As a result of this paper, this paper strives to compare and contrast mobile learning with normal learning in medicine from various perspectives and give insights and advises into the essential characteristics of both for sustaining medical education.

  20. Mobil Viral Pazarlama

    OpenAIRE

    Barutçu, Süleyman

    2011-01-01

    OBJECTIVE: Mobile Viral Marketing, with using mobile phones, is one of the most importantinnovations after Word of Mouth Marketing performed by face to face amongpeople and Viral Marketing performed in the İnternet. The main objective of thisstudy is to call marketing communicators’ and academicians’ attentions whowant to increase the recognition of companies’ products, services and brands tobecome a current issue in the marketplace using Mobile Viral Marketingapplications by reason of techno...

  1. Keeping communication mobile

    International Nuclear Information System (INIS)

    Latimer, Cole

    2010-01-01

    While mobile phones are ubiquitous in nearly all walks of Australia industry, there is still one sector were the technology has been unsurprisingly absent. Aside from the obvious operational hazards that a mobile phone would encounter when being used underground, such as harsh working conditions, dust and heavy knocks, the technology required to actually use a mobile at depths has been in the early stages for some time. However and Australian company, Mine Site Technologies, has taken a leap into this space by designing the world's first mobile phone for underground mining

  2. Mobile Solar Tracker Facility

    Data.gov (United States)

    Federal Laboratory Consortium — NIST's mobile solar tracking facility is used to characterize the electrical performance of photovoltaic panels. It incorporates meteorological instruments, a solar...

  3. Programming the Mobile Web

    CERN Document Server

    Firtman, Maximiliano

    2010-01-01

    Today's market for mobile apps goes beyond the iPhone to include BlackBerry, Nokia, Windows Phone, and smartphones powered by Android, webOS, and other platforms. If you're an experienced web developer, this book shows you how to build a standard app core that you can extend to work with specific devices. You'll learn the particulars and pitfalls of building mobile apps with HTML, CSS, and other standard web tools. You'll also explore platform variations, finicky mobile browsers, Ajax design patterns for mobile, and much more. Before you know it, you'll be able to create mashups using Web 2.

  4. Mobile Test Capabilities

    Data.gov (United States)

    Federal Laboratory Consortium — The Electrical Power Mobile Test capabilities are utilized to conduct electrical power quality testing on aircraft and helicopters. This capability allows that the...

  5. Best Sale Mobile Application

    OpenAIRE

    Chittugnanamoorthy, Balakumar

    2014-01-01

    The aim of this thesis was to find a best way to advertise short-term sales and reduce paper waste. Another aim was to help the seller to identify a potential customer for a specific product, by means of providing a number of people accessing an advertisement. A mobile phone is one of the widely used electronic devices by many people. Modern mobile phones support a good internet connection. Also, people carry their mobile devices with them even outside their homes. So a mobile application ...

  6. Proxemic Mobile Collocated Interactions

    DEFF Research Database (Denmark)

    Porcheron, Martin; Lucero, Andrés; Quigley, Aaron

    2016-01-01

    and their digital devices (i.e. the proxemic relationships). Building on the ideas of proxemic interactions, this workshop is motivated by the concept of ‘proxemic mobile collocated interactions’, to harness new or existing technologies to create engaging and interactionally relevant experiences. Such approaches......Recent research on mobile collocated interactions has been looking at situations in which collocated users engage in collaborative activities using their mobile devices. However, existing practices fail to fully account for the culturally-dependent spatial relationships between people...... in exploring proxemics and mobile collocated interactions....

  7. Practical mobile forensics

    CERN Document Server

    Bommisetty, Satish; Mahalik, Heather

    2014-01-01

    The book is an easy-to-follow guide with clear instructions on various mobile forensic techniques. The chapters and the topics within are structured for a smooth learning curve, which will swiftly empower you to master mobile forensics. If you are a budding forensic analyst, consultant, engineer, or a forensic professional wanting to expand your skillset, this is the book for you. The book will also be beneficial to those with an interest in mobile forensics or wanting to find data lost on mobile devices. It will be helpful to be familiar with forensics in general but no prior experience is re

  8. Mobile computing handbook

    CERN Document Server

    Ilyas, Mohammad

    2004-01-01

    INTRODUCTION AND APPLICATIONS OF MOBILE COMPUTING Wearable Computing,A. Smailagic and D.P. Siewiorek Developing Mobile Applications: A Lime Primer,G.P. Picco, A.L. Murphy, and G.-C. Roman Pervasive Application Development: Approaches and Pitfalls,G. Banavar, N. Cohen, and D. Soroker ISAM, Joining Context-Awareness and Mobility to Building Pervasive Applications,I. Augustin, A. Corrêa Yamin, J.L. Victória Barbosa, L. Cavalheiro da Silva, R. Araújo Real, G. Frainer, G.G. Honrich Cavalheiro, and C.F. Resin Geyer Integrating Mobile Wireless Devices into the Computational Grid,T. Phan, L. Huan

  9. Cooperative Mobile Web Browsing

    DEFF Research Database (Denmark)

    Perrucci, GP; Fitzek, FHP; Zhang, Qi

    2009-01-01

    This paper advocates a novel approach for mobile web browsing based on cooperation among wireless devices within close proximity operating in a cellular environment. In the actual state of the art, mobile phones can access the web using different cellular technologies. However, the supported data......-range links can then be used for cooperative mobile web browsing. By implementing the cooperative web browsing on commercial mobile phones, it will be shown that better performance is achieved in terms of increased data rate and therefore reduced access times, resulting in a significantly enhanced web...

  10. Mobile Project Management

    Directory of Open Access Journals (Sweden)

    Catalin BOJA

    2006-01-01

    Full Text Available Based on the development of new communication and data transfer technologies, the mobile solutions for the management process have been able to provide new ways to conduct management actions. This environment describes methods and tools available only here, which will bring information, speed and efficiency to any stage and component of the management process. The paper takes into discussion the impact of the technological development on the management process paradigm. The paper presents the main aspects regarding the business and management models used in mobile management. The role of mobile multimedia informatics applications in mobile management is highlighted.

  11. Mobility Charters and Manifestos

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    2010-01-01

    This paper explore a number of different cases of articulating notions of ‘correct’ mobility behavior and practice by looking into charters, manifestos and codes of mobility regulation. Within such discourses of ‘correct mobility’ more or less subtle expressions of power as well as normative and ...... ‘Highway Code Booklets’ from the 1930’s, 40’s and 50’s, the ‘City Slow Charter’, the ‘New Urbanism Charter’ as attempts to codify and order mobility and mobile practices.......This paper explore a number of different cases of articulating notions of ‘correct’ mobility behavior and practice by looking into charters, manifestos and codes of mobility regulation. Within such discourses of ‘correct mobility’ more or less subtle expressions of power as well as normative...... and ethical positions on mobility prevail. Such ‘imagined correct mobility behavior’ are drawing on larger issues of societal change that need to be brought out in a critical analysis and discussion reflecting the attempts to control, design and orchestrate mobility patterns. The paper therefore argues within...

  12. The setup of a mobile mobility panel for the Netherlands

    NARCIS (Netherlands)

    Geurs, Karst Teunis; Veenstra, Sander; Thomas, Tom

    2013-01-01

    This paper describes the setup of the Dutch Mobile Mobility Panel project, in which GPS-enabled mobile phones (smartphones) are used as a passive multiple-week and multiple-year travel behaviour data collection tool. The data collection methodology used in the Dutch Mobile Mobility Panel comprised

  13. Mobile lifestyles : Conceptualizing heterogeneity in mobile youth culture

    NARCIS (Netherlands)

    Vanden Abeele, M.M.P.

    2014-01-01

    Adolescents’ characteristic understanding and use of mobile phones have led observers to speak of a “mobile youth culture.” This article explores whether we can differentiate lifestyles within mobile youth culture. We construct a user typology of Flemish adolescent mobile phone users based on mobile

  14. A Carrier Bag Story of (waste) food, hens and the sharing economy

    DEFF Research Database (Denmark)

    Fjalland, Emmy Laura Perez

    2018-01-01

    futures by showing the collaborative, compassionate, responsible qualities of the sharing economy of the exchange of waste food. With the help from The Carrier Bag Theory – an alternative, feminist narrative – and the mobilities paradigm, this article shows the transformative gestures of ethical......, ecologies and different waste, recycling and/or upcycling systems. Within these disposal systems, valuable resources are being lost. Based on empirical work from a Danish project called Sharing City and a local small-scale organic farm (named Hegnsholt), this article elaborates upon how particular waste......, this article ought to inspire us to rethink how to share this planet with earth-others....

  15. Dicyclohexano-18-crown-6 as a novel carrier in the liquid membrane permeation of actinides

    International Nuclear Information System (INIS)

    Kumar, Anil; Singh, R.K.; Bajpai, D.D.; Shukla, J.P.

    1994-01-01

    The proven extractability and profound selectivity of dicyclohexano-18-crown-6 (DC18C6) has been exploited by selecting this crown ether as the ionophore in liquid membrane transport. Macrocycle-facilitated transport of Pu(IV) and U(VI) against their concentration gradient from aqueous nitric acid solutions across organic bulk liquid membrane (BLM) and thin-sheet supported liquid membrane (SLM) containing DC18C6 as the mobile carrier and toluene as the membrane solvent was investigated. (author). 23 refs., 9 tabs., 7 figs

  16. Top-gate dielectric induced doping and scattering of charge carriers in epitaxial graphene

    Science.gov (United States)

    Puls, Conor P.; Staley, Neal E.; Moon, Jeong-Sun; Robinson, Joshua A.; Campbell, Paul M.; Tedesco, Joseph L.; Myers-Ward, Rachael L.; Eddy, Charles R.; Gaskill, D. Kurt; Liu, Ying

    2011-07-01

    We show that an e-gun deposited dielectric impose severe limits on epitaxial graphene-based device performance based on Raman spectroscopy and low-temperature transport measurements. Specifically, we show from studies of epitaxial graphene Hall bars covered by SiO2 that the measured carrier density is strongly inhomogenous and predominantly induced by charged impurities at the grapheme/dielectric interface that limit mobility via Coulomb interactions. Our work emphasizes that material integration of epitaxial graphene and a gate dielectric is the next major road block towards the realization of graphene-based electronics.

  17. Multi-user MIMO and carrier aggregation in 4G systems

    DEFF Research Database (Denmark)

    Cattoni, Andrea Fabio; Nguyen, Hung Tuan; Duplicy, Jonathan

    2012-01-01

    The market success of broadband multimediaenabled devices such as smart phones, tablets, and laptops is increasing the demand for wireless data capacity in mobile cellular systems. In order to meet such requirements, the introduction of advanced techniques for increasing the efficiency in spectrum...... usage was required. Multi User -Multiple Input Multiple Output (MU-MIMO) and Carrier Aggregation (CA) are two important techniques addressed by 3GPP for LTE and LTE-Advanced. The aim of the EU FP7 project on ”Spectrum Aggregation and Multiuser-MIMO: real-World Impact” (SAMURAI) is to investigate...

  18. Carrier-interleaved orthogonal multi-electrode multi-carrier resistivity-measurement tool

    International Nuclear Information System (INIS)

    Cai, Yu; Sha, Shuang

    2016-01-01

    This paper proposes a new carrier-interleaved orthogonal multi-electrode multi-carrier resistivity-measurement tool used in a cylindrical borehole environment during oil-based mud drilling processes. The new tool is an orthogonal frequency division multiplexing access-based contactless multi-measurand detection tool. The tool can measure formation resistivity in different azimuthal angles and elevational depths. It can measure many more measurands simultaneously in a specified bandwidth than the legacy frequency division multiplexing multi-measurand tool without a channel-select filter while avoiding inter-carrier interference. The paper also shows that formation resistivity is not sensitive to frequency in certain frequency bands. The average resistivity collected from N subcarriers can increase the measurement of the signal-to-noise ratio (SNR) by N times given no amplitude clipping in the current-injection electrode. If the clipping limit is taken into account, with the phase rotation of each single carrier, the amplitude peak-to-average ratio can be reduced by 3 times, and the SNR can achieve a 9/ N times gain over the single-carrier system. The carrier-interleaving technique is also introduced to counter the carrier frequency offset (CFO) effect, where the CFO will cause inter-pad interference. A qualitative analysis and simulations demonstrate that block-interleaving performs better than tone-interleaving when coping with a large CFO. The theoretical analysis also suggests that increasing the subcarrier number can increase the measurement speed or enhance elevational resolution without sacrificing receiver performance. The complex orthogonal multi-pad multi-carrier resistivity logging tool, in which all subcarriers are complex signals, can provide a larger available subcarrier pool than other types of transceivers. (paper)

  19. Fundamental limits on the electron mobility of β-Ga2O3.

    Science.gov (United States)

    Kang, Youngho; Krishnaswamy, Karthik; Peelaers, Hartwin; Van de Walle, Chris G

    2017-06-14

    We perform first-principles calculations to investigate the electronic and vibrational spectra and the electron mobility of β-Ga 2 O 3 . We calculate the electron-phonon scattering rate of the polar optical phonon modes using the Vogl model in conjunction with Fermi's golden rule; this enables us to fully take the anisotropic phonon spectra of the monoclinic lattice of β-Ga 2 O 3 into account. We also examine the scattering rate due to ionized impurities or defects using a Yukawa-potential-based model. We consider scattering due to donor impurities, as well as the possibility of compensation by acceptors such as Ga vacancies. We then calculate the room-temperature mobility of β-Ga 2 O 3 using the Boltzmann transport equation within the relaxation time approximation, for carrier densities in the range from 10 17 to 10 20 cm -3 . We find that the electron-phonon interaction dominates the mobility for carrier densities of up to 10 19 cm -3 . We also find that the intrinsic anisotropy in the mobility is small; experimental findings of large anisotropy must therefore be attributed to other factors. We attribute the experimentally observed reduction of the mobility with increasing carrier density to increasing levels of compensation, which significantly affect the mobility.

  20. Fundamental limits on the electron mobility of β-Ga2O3

    Science.gov (United States)

    Kang, Youngho; Krishnaswamy, Karthik; Peelaers, Hartwin; Van de Walle, Chris G.

    2017-06-01

    We perform first-principles calculations to investigate the electronic and vibrational spectra and the electron mobility of β-Ga2O3. We calculate the electron-phonon scattering rate of the polar optical phonon modes using the Vogl model in conjunction with Fermi’s golden rule; this enables us to fully take the anisotropic phonon spectra of the monoclinic lattice of β-Ga2O3 into account. We also examine the scattering rate due to ionized impurities or defects using a Yukawa-potential-based model. We consider scattering due to donor impurities, as well as the possibility of compensation by acceptors such as Ga vacancies. We then calculate the room-temperature mobility of β-Ga2O3 using the Boltzmann transport equation within the relaxation time approximation, for carrier densities in the range from 1017 to 1020 cm-3. We find that the electron-phonon interaction dominates the mobility for carrier densities of up to 1019 cm-3. We also find that the intrinsic anisotropy in the mobility is small; experimental findings of large anisotropy must therefore be attributed to other factors. We attribute the experimentally observed reduction of the mobility with increasing carrier density to increasing levels of compensation, which significantly affect the mobility.