Temperature Coefficient of Resistivity in Amorphous Semiconductors

TL;DR

This paper derives explicit formulas for electrical conductivity and TCR in amorphous semiconductors using microscopic response theory, aligning predictions with experiments and resolving a long-standing anomaly in conductivity behavior.

Contribution

It provides new analytical expressions for conductivity and TCR in amorphous semiconductors, clarifying the roles of localized and extended state transitions.

Findings

Predicted TCR matches experimental data for a-Si:H and a-Ge:H.

Conductivity from localized-extended state transitions is comparable to localized-localized transitions.

Resolves the 'kink' anomaly in the log conductivity versus inverse temperature curve.

Abstract

By invoking the microscopic response method in conjunction with a reasonable set of approximations, we obtain new explicit expressions for the electrical conductivity and temperature coefficient of resistivity (TCR) in amorphous semiconductors, especially a-Si:H and a-Ge:H. The predicted TCR for n-doped a-Si:H and a-Ge:H is in agreement with experiments. The conductivity from the transitions from a localized state to an extended state (LE) is comparable to that from the transitions between two localized states (LL). This resolves a long-standing anomaly, a "kink" in the experimental $\log_{10}\sigma $ vs. T$^{-1}$ curve.