Photo-Seebeck Effect in ZnO

TL;DR

This study investigates how light illumination affects the thermoelectric properties of ZnO, revealing that photo-induced carriers significantly alter conductivity and Seebeck coefficient, with implications for light-controlled thermoelectric applications.

Contribution

It is the first to analyze the photo-Seebeck effect in ZnO, demonstrating how light influences carrier dynamics and thermoelectric properties in this wide-gap oxide semiconductor.

Findings

Light illumination changes Seebeck coefficient and conductivity.

Photo-induced carriers increase carrier concentration and mobility.

The behavior resembles doped semiconductors.

Abstract

We examine how the photo-induced carriers contribute the thermoelectric transport, i.e. the nature of the photo-Seebeck effect, in the wide-gap oxide semiconductor ZnO for the first time. We measure the electrical conductivity and the Seebeck coefficient with illuminating light. The light illumination considerably changes the Seebeck coefficient as well as the conductivity, which is sensitive to the photon energy of the illuminated light. By using a simple parallel-circuit model, we evaluate the contributions of the photo-induced carriers to the conductivity and the Seebeck coefficient, whose relationship shows a remarkable resemblance to that in doped semiconductors. Our results also demonstrate that the light illumination increases both the carrier concentration and the mobility, which can be compared with impurity-doping case for ZnO. Future prospects for thermoelectrics using light are discussed.