# Absolute Seebeck coefficient of thin platinum films

## TL;DR

This study investigates how size effects in thin platinum films influence their thermoelectric properties, particularly the Seebeck coefficient, revealing reductions compared to bulk platinum due to boundary and surface scattering effects.

## Contribution

It provides a standardized measurement method for the absolute Seebeck coefficient of thin platinum films and models the impact of size effects on thermoelectric behavior.

## Key findings

- Seebeck coefficient is reduced in thin films compared to bulk platinum.
- Boundary and surface scattering diminish thermodiffusion and phonon drag contributions.
- A model describes temperature dependence and size effects on $S_{Pt}$.

## Abstract

The influence of size effects on the thermoelectric properties of thin platinum films is investigated and compared to the bulk. Structural properties, like the film thickness and the grain size, are varied. We correlate the electron mean free path with the temperature dependence of the electrical conductivity and the absolute Seebeck coefficient $S_{\text{Pt}}$ of platinum. We use a measurement platform as a standardized method to determine $S_{\text{Pt}}$ and show that $S_{\text{Pt,film}}$ is reduced compared to $S_{\text{Pt,bulk}}$. Boundary and surface scattering reduce the thermodiffusion and the phonon drag contribution to $S_{\text{Pt,film}}$ by nearly the same factor. A detailed discussion and a model to describe the temperature dependence of the absolute Seebeck coefficient and the influence of size effects of electron-phonon and phonon-phonon interaction on $S_{\text{Pt}}$ is given.