Magnetoconductivity of Hubbard bands induced in silicon MOSFETs

Sodium impurities are diffused electrically to the oxide-semiconductor interface of a silicon MOSFET to create an impurity band. At low temperature and at low electron density, the band is split into an upper and a lower sections under the influence of Coulomb interactions. We used magnetoconductivity measurements to provide evidence for the existence of Hubbard bands and determine the nature of the states in each band.     

Enhanced magnetoconductivity and electrical property of MWCNT-CdS nanocomposite embedded in polyaniline

PANI/MWCNT-CdS nanocomposites with different content of CdS wt.% has been synthesized by the chemical oxidative in-situ polymerization reaction of aniline in the presence of multi-walled carbon nanotubes (MWCNT). TEM, XRD, FTIR, and TGA studies were done for the structural and thermal characterization of the samples respectively. The particle size of CdS nanoparticles distributes in between 2.7 and 4.8 nm. XRD spectrum reveals that the co-existence of MWCNT, CdS in PANI matrix, where CdS forms a hexagonal structure. TGA result shows that nanocomposite becomes more thermally stable with the increase in CdS content. The dc electrical transport property of PANI/MWCNT-CdS nanocomposites has been investigated within a temperature range 77 ≤ T ≤ 300 K. The dc conductivity follows a 3D variable range hopping (VRH) model. A large magnetoconductivity change (19%) is observed for 2 wt% CdS content in PANI/MWCNT-CdS, which is explained by the wave function shrinkage model.     

Magnetoconductivity tensor analysis of anomalous transport effects in neutron irradiated HgCdTe epilayers

Hg_1−xCd_xTe(x0.22) samples grown by LPE on CdZnTe(111B)-oriented substrates were exposed to various doses of thermal neutrons (1.0×10¹⁶−1.7×10¹⁶ n/cm²) and subsequently annealed for 24 h in Hg overpressure to remove damage and reduce the presence of Hg vacancies. Extensive magnetotransport measurements were performed on these samples as part of an investigation into the use of elemental transmutation for efficient p-type doping of this material. The data were analyzed using a multi-carrier approach which incorporates various scattering mechanisms and the presence of two conduction channels of differing alloy content to describe the changes in the transport properties due to neutron irradiation.