Transport Properties in InAs Thin Films with Different Degrees of Disorder Near the Metal–Insulator Transition
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Transport properties of Indium Arsenide (InAs) films deposited at different working pressures are investigated in the temperature interval of T ∼ 2–250 K. 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 μc-InAs samples. The critical conductivity exponent of μc-InAs is close to 1, which indicates that μc-InAs samples exhibit a close proximity to the metal–insulator transition. The product of aB and n1/3 for samples S1 and S2 is 0.236 and 0.207, respectively, which is roughly consistent with the Mott criterion. But for α-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 α-InAs thin films at low temperatures.
KeywordsInAs thin films MIT transport properties Mott VRH ES VRH
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Funding was provided by National Natural Science Foundation of China (Grant No. 61356002).
Conflict of interest
The authors declare that they have no conflict of interest.
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