Magneto-Optic and Quantum Transport Studies of MBE InSb and InAs

Abstract

The MBE growth and doping of the narrow gap materials InSb and InAs are studied. Magneto-optical experiments are extremely informative in the case of high purity films of InAs showing the presence both of a low mobility accumulation layer and a high mobility bulk region and enabling the galvanomagnetic properties to be interpreted in terms of parallel conductance involving the two regions. Silicon can be incorporated fully as a donor up to concentrations of 3×10¹⁸cm⁻³ in the case of InSb and 6×10¹⁹ cm⁻³ with InAs. The control of silicon doping is utilised to prepare high-concentration spike-doped samples and nipi structures showing enhanced subband gap absorption, large optical non-linearities and increased carrier lifetimes. Shubnikov-de Haas measurements are undertaken with the spike-doped samples to determine the subband occupancy and to investigate possible dopant diffusion.