Hall effect in the accumulation layers on the surface of organic semiconductors

TL;DR

This study reports the observation of the Hall effect in organic semiconductor surface layers, revealing temperature-dependent mobility and charge carrier behavior consistent with band-like conduction.

Contribution

It provides the first direct measurement of the Hall effect in organic semiconductor accumulation layers, demonstrating diffusive band-like charge transport.

Findings

Hall mobility increases as temperature decreases

Hall carrier density matches calculated density in intrinsic regime

Charge transport is consistent with band-like motion

Abstract

We have observed the Hall effect in the field-induced accumulation layer on the surface of small-molecule organic semiconductor. The Hall mobility mu_H increases with decreasing temperature in both the intrinsic (high-temperature) and trap-dominated (low-temperature) conduction regimes. In the intrinsic regime, the density of mobile field-induced charge carriers extracted from the Hall measurements, n_H, coincides with the density n calculated using the gate-channel capacitance, and becomes smaller than n in the trap-dominated regime. The Hall data are consistent with the diffusive band-like motion of field-induced charge carriers between the trapping events.