Thermoelectric efficiency in the space-charge-limited transport regime in semiconductors

TL;DR

This paper explores thermoelectric efficiency in semiconductors under space-charge-limited transport, revealing a new figure of merit and highlighting nanowires as the most promising material for this regime.

Contribution

It introduces a novel framework for thermoelectric efficiency in the space-charge-limited regime and compares different material geometries.

Findings

Efficiency can be characterized by a single figure of merit in this regime

Nanowires are identified as the most promising for thermoelectric applications

The study extends thermoelectric analysis beyond the ohmic regime

Abstract

The thermoelectric efficiency of semiconductors is usually considered in the ohmic electronic transport regime, which is achieved through high doping. Here we consider the opposite regime of low doping where the current-voltage characteristics are nonlinear and dominated by space-charge-limited transport. We show that in this regime, the thermoelectric efficiency can be described by a single figure of merit, in analogy with the ohmic case. Efficiencies for bulk, thin film, and nanowire materials are discussed, and it is proposed that nanowires are the most promising to take advantage of space-charge-limited transport for thermoelectrics.