On the mobility and diffusion length of electrons in p-type indium antimonide

The results are presented on the behaviour of electrons in p-type InSb doped with germanium investigated by spectral and volt-ampere characteristics of sharp asymmetric alloyed n+p-junctions. Measurement of electron diffusive lengths is based on the analysis of changing spectral curves of photocurrent with decreasing the depth of the p+n-junction penetration. The electron diffusive lengths measured show a distinct dependence on the hole concentration in p-InSb. At T=90 K the diffusion coefficient is equal to 0.12 m2/S, that corresponds to the value of the effective mobility of electrons (1.6-2.4)x10 m2/V.s. As the temperature increases up to 160 K the diffusion coefficient decreases to values of (4-8)x10-3 m2/S; the effective mobility drops by two orders approximately, that corresponds to hole mobility. At low temperatures is observed diffusion of electrons produced by light at a surface. With increasing temperature the diffusion acquires an ambipolar character. It has been thus established that holes affect considerably the behaviour of electrons in p-InSb in the temperature range 80-160 K