Guo Shao-Ling

Composition dependence of hot electron effect in Hg1-xCdxTe

A number of Hg1-xCdxTe samples of different composition (x=0.18-0.50) have been investigated at low temperatures of 0.3-4.2 K in magnetic fields of 0-7 T. A group of non-linear I-V relations have been observed. The experimental results show that the electron concentration, mobility, composition and crystal quality all influence the hot electron effect.

MAGNETIC-FIELD-INDUCED METAL-INSULATOR TRANSITION AND THERMALLY ACTIVATED ELECTRONIC TRANSPORT IN LOW COMPENSATED n-Hg 1-x Cd x Te

Transverse magnet ores istance, electronic mobility and Hall coefficient of low compensated (K《1)n-Hg1-xCdxTe(x=0.214) have been measured at low temperatures from 0.3K to 30K and high magnetic field up to 7T. Magnetic-field-induced metal-insulator transition (MIT) has been found in our sample. According to the experimental data, we suggest that the mechanism of the magnetic induced MIT in low copmensated n-Hg1-xCdxTe (x is around 0.2) is magnetic freeze-out of carriers to shallow impurity states. Prerequisite condition of the magnetic freeze-out is thermal freeze-out which forces the carriers from conduction band to shallow impurity state at very low temperature. Thermally activated conduction of electrons can be described by the expression ＲH（Ｔ）＝ＲH0exp[a/kT]. It represents the thermally activated process of electrons bound in impurity state. From activation energy of the conductivity in nonmetallic region, we infer that there are two shallow impurity states in the sample.