Charge transport in the spatially correlated exponential random energy landscape: effect of the non-positive correlation function

TL;DR

This paper analyzes charge transport in amorphous semiconductors with spatially correlated exponential density of states, revealing how non-positive correlations affect transition temperatures and mobility decay.

Contribution

It provides an exact calculation of average carrier velocity considering arbitrary correlation functions and highlights the impact of non-positive correlations on transport properties.

Findings

Transition temperature depends on correlation properties and exceeds traditional estimates.

Mobility decays with field in low field regions due to non-positive correlations.

Exact velocity calculations for quasi-equilibrium transport regime.

Abstract

Charge transport in amorphous semiconductors having spatially correlated exponential density of states (DOS) has been considered for the arbitrary behavior of the correlation function of random energies. Average carrier velocity is exactly calculated for the quasi-equilibrium (nondispersive) transport regime. For the symmetric exponential DOS with exponential tails for low and high energies and non-positive correlation function the temperature for the transition to the dispersive transport regime depends on correlation properties and becomes greater than the traditional estimation based on the DOS decay energy $kT=U_0$. Another new feature of the transport in the landscape having non-positive correlation function is the decay of the mobility with field in low field region.