Transport Properties in InAs Thin Films with Different Degrees of Disorder Near the Metal-Insulator Transition

Transport properties of Indium Arsenide (InAs) films deposited at different working pressures are investigated in the temperature interval of T approximate to 2-250K. Electrical transport of InAs films is related to the degree of disorder, which increases as working pressure increases. Activated conductivity models satisfactorily describe conduction in the localized band-tails at high temperatures, while conductivity shows metallic characteristic at low temperatures for c-InAs samples. The critical conductivity exponent of c-InAs is close to 1, which indicates that c-InAs samples exhibit a close proximity to the metal-insulator transition. The product of a(B) and n(1/3) for samples S1 and S2 is 0.236 and 0.207, respectively, which is roughly consistent with the Mott criterion. But for -InAs samples in the high temperature region, electron transport is described by conduction in extended states and in localized states near the Fermi level. Furthermore, a crossover from Mott variable range hopping (VRH) to the Efros-Shklovskii VRH mechanism is observed in -InAs thin films at low temperatures.