STUDIES ON THERMAL VARIATION OF DRIFT MOBILITY AND MEAN FREE TIME FOR HOLES AND ELECTRONS IN GAAS.

Abstract

The electronic properties of semiconducting materials are significantly temperature dependent. To predict variation of electronic device functions with temperature, it is important to have knowledge of variation of fundamental electronic properties of semiconducting materials. These fundamental properties include bandgap energy Eg, electronic conductivity σ, intrinsic electronic conductivity σi, carrier mobility µ, intrinsic carrier mobility µi, diffusion coefficient D, diffusion length L, mean free time τ, intrinsic carrier concentration ni, and Fermi energy level EF. This research work however involved theoretical computations of drift mobility and mean free time for electrons and holes in GaAs at different temperatures in the range 0 – 500 K; using some experimental data deduced from a graph of Hall mobility, µH versus temperature, T available mostly at room temperature and some at low temperatures - and using the theoretical formulations developed in this work. The research work resulted in tables and graphs of variation with temperature of electron drift mobility µnd, hole drift mobility µpd, intrinsic carrier mobility µi, mean free time for electrons τn and mean free time for holes τp in GaAs. The results so obtained are expected to be useful for future prediction of variation of functions of electronic devices made of GaAs.