D.c. galvanomagnetic properties in a heavily compensated single crystal of n-type CdTe

Abstract

Experimental data on d.c. galvanomagnetic properties, namely the Hall coefficientR _H, the low-electric-field d.c. conductivityσ and the Hall mobilityμ _H, in a heavily compensated single crystal of n-type CdTe in the temperature range 77 to 300 K have been analysed, firstly on the basis of a simple one-band model involving normal free-electron conduction, and secondly on the basis of a two-band model involving normal free-electron conduction along with impurity-band conduction. The analysis provides evidence for a significant contribution of impurityband conduction to the transport phenomena at temperatures below ∼ 150 K. This conclusion is further substantiated by transverse magnetoresistance measurements and the observed dependence of d.c. conductivity on the electric field. From the analysis of these data, the average hopping distanceR in the impurity band is calculated, and it is found to increase with decrease of temperature. The relative contributions of normal free-electron conduction and impurity-band conduction to the d.c. galvanomagnetic properties are estimated at different temperatures.