The effect of nonparabolicity on electron transport in semiconductor thin films

Abstract

The resistivity of semiconductor thin films of InSb and GaAs at 77 K is investigated in the ultrathin limit with energy band nonparabolicity taken into account. The calculation based on the balance equation theory shows that the resistivity of these samples deviates from the previous result obtained by Arora and Awad for the parabolic limit (1981 Phys. Rev. B 23 5570) which stated that the ratio of film resistivity to bulk resistivity is inversely proportional to d (the thickness of the film). The ratio is larger than unity when the thickness d is less than 100 nm and becomes larger with decreasing thickness of film. The nonparabolicity of the energy band results in the increase of the ratio and the increase of the deviation of the present result from the previous result for the parabolic limit.