# Temperature dependence of the Seebeck coefficient of epitaxial $\beta$-Ga$_2$O$_3$ thin films

## TL;DR

This study investigates how the Seebeck coefficient of silicon-doped epitaxial $eta$-Ga$_2$O$_3$ thin films varies with temperature, revealing the dominant scattering mechanisms and their effects on thermoelectric properties.

## Contribution

It provides the first detailed analysis of temperature-dependent Seebeck coefficient behavior in epitaxial $eta$-Ga$_2$O$_3$ thin films, including scattering mechanism insights.

## Key findings

- Seebeck coefficient at room temperature is approximately -300 μV/K.
- Electron-phonon interaction dominates scattering above 240 K.
- Lower temperatures show increased Seebeck magnitude explained by Stratton's formula.

## Abstract

The temperature dependence of the Seebeck coefficient of homoepitaxial metal organic vapor phase (MOVPE) grown, silicon doped $\beta$-Ga$_2$O$_3$ thin films was measured relative to aluminum. For room temperature we found the relative Seebeck coefficient of $S_{\beta\text{-Ga}_2\text{O}_3\text{-Al}}=(-300\pm20)\;\mu$V/K. At high bath temperatures $T>240$ K, the scattering is determined by electron-phonon-interaction. At lower bath temperatures between $T=100$ K and $T=300$ K, an increase in the magnitude of the Seebeck coefficient is explained in the frame of Strattons formula. The influence of the different scattering mechanisms on the magnitude of the Seebeck coefficient is discussed and compared with Hall measurement results.