Papers by Keyword: Hall Measurements

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Authors: Peediyekkal Jayaram, T.P. Jaya, P.P. Pradyumnan
Abstract: This work reports the synthesis of novel quaternary transparent conducting oxide Cd(1-x)Sn(1-x)InxGaxO3( x=0.1, 0.2, 0.3) at 1225°C via solid state reaction route. The investigations on structural, optical and electrical properties have been carried out. Powder X-ray diffraction revealed the phase purity and distorted orthorhombic structure of the species synthesized. Distortion of the structure is due to the substitution of In3+ and Ga3+ in CdSnO3 (JCPDS card no.340885) matrix. The optical transmittance approximated by the reflectance shows considerable increase in the transmittance of visible light along with the increase of substitution. Typical Burstein-Moss effect is observed with the increase in x value as a variation in optical bandgap from 2.7 to 2.9eV. Four point Hall measurements by Van der-Pauw method exhibit superior properties in charge carrier concentration and mobility. Maximum bulk charge concentration of 4.78x1017 cm-3 is obtained for x=0.3. Hall mobility depends on carrier concentration and steeply increases with the carrier concentration. Considerable drop in the resistivity of the material along with higher transmittance is a critical finding in the experiment.
Authors: K. Narita, Yasuto Hijikata, Hiroyuki Yaguchi, Sadafumi Yoshida, Junji Senzaki, Shinichi Nakashima
Authors: Harry L. Kwok
Abstract: Hall measurement is an effective means to measure carrier density and mobility in metals and semiconductors. This work examined the carrier mobility determined in the accumulation layer of organic field-effect transistors (OFETS) and proposed a method to explain data taken from rubrene single-crystal devices. The model was used to extract information on the trap states and the properties of the transport layer at different temperature.
Authors: Phillippe Godignon, Christophe Jacquier, Servane Blanqué, Josep Montserrat, Gabriel Ferro, Sylvie Contreras, Marcin Zielinski, Yves Monteil
Authors: Y. Wang, D.H. Zhang, Y.J. Jin, X.Z. Chen, J.H. Li
Abstract: We report the electrical properties of the InSbN alloys fabricated by two-step implantation of nitrogen ions into InSb wafers, characterized by Hall measurements. The alloy with higher implanted dose shows lower electron concentration due to the acceptor nature of nitrogen. At temperatures below 150 K, the electron concentration does not change and follows an exponential relation at above 200 K. The Hall mobility in all samples monotonically decreases with the increase of temperature, indicating the phonon dominating scattering mechanism. The annealing results reveal that annealing temperatures up to 598 K make the carrier concentration lower due to the reduction of donor-type defects caused by ion implantation and the acceptor nature of nitrogen.
Authors: Brenda L. VanMil, Rachael L. Myers-Ward, Joseph L. Tedesco, Charles R. Eddy, Glenn G. Jernigan, James C. Culbertson, Paul M. Campbell, J.M. McCrate, S.A. Kitt, D. Kurt Gaskill
Abstract: Graphene layers were created on both C and Si faces of semi-insulating, on-axis, 4H- and 6H-SiC substrates. The process was performed under high vacuum (<10-4 mbar) in a commercial chemical vapor deposition SiC reactor. A method for H2 etching the on-axis substrates was developed to produce surface steps with heights of 0.5 nm on the Si-face and 1.0 to 1.5 nm on the C-face for each polytype. A process was developed to form graphene on the substrates immediately after H2 etching and Raman spectroscopy of these samples confirmed the formation of graphene. The morphology of the graphene is described. For both faces, the underlying substrate morphology was significantly modified during graphene formation; surface steps were up to 15 nm high and the uni-form step morphology was sometimes lost. Mobilities and sheet carrier concentrations derived from Hall Effect measurements on large area (16 mm square) and small area (2 and 10 m square) samples are presented and shown to compare favorably to recent reports.
Authors: W. Wang, S. Banerjee, T. Paul Chow, Ronald J. Gutmann, Tamara Isaacs-Smith, John R. Williams, Kenneth A. Jones, Aivars J. Lelis, W. Tipton, Skip Scozzie, Anant K. Agarwal
Authors: M. Bouroushian, T. Kosanovic
Abstract: A variety of electrochemical and electrical techniques is employed in order to determine useful parameters of the optical behaviour of thin semiconducting films. In particular, this work is intended to the characterization of cathodically electrodeposited binary and ternary cadmium and zinc selenides and tellurides by photoelectrochemical (PEC) tests. Typical solid-state techniques, such as reflection, laser assisted photoreflection, resistivity and Hall effect measurements are used as well. A plain relation between crystal structure/film morphology and PEC behavior is established so long as the electrochemical preparation method is capable to explicitly control the deposit structure. In certain cases, a particular charge transfer mechanism in the semiconductor, associated with the existence of a nanostructure, is shown to result in higher photoconversion efficiencies as compared to larger-grained films.
Authors: Sarit Dhar, Ayayi Claude Ahyi, John R. Williams, Sei Hyung Ryu, Anant K. Agarwal
Abstract: Hall measurements on NO annealed 4H-SiC MOS gated Hall bars are reported in the temperature range 77 K- 423 K. The results indicate higher carrier concentration and lower trapping at increased temperatures, with a clear strong inversion regime at all temperatures. In stark contrast to Si, the Hall mobility increases with temperature for 77 K-373K, above which the mobility decreases slightly. The maximum experimental mobility was found to be ~50 cm2 V-1 s-1 which is only about 10% of the 4H-SiC bulk mobility indicating that while NO annealing drastically improves trapping, it does not improve the mobility significantly. Supporting modeling results strongly suggest the presence of a disordered SiC channel region.
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