Electric field modulation of thermopower for transparent amorphous oxide thin film transistors

TL;DR

This study investigates how electric fields influence thermopower in transparent amorphous oxide transistors, revealing unique behaviors linked to the electronic density of states near the conduction band edge.

Contribution

It provides new insights into the DOS structure of TAOSs by analyzing thermopower behavior under gate voltage modulation in fabricated TTFTs.

Findings

Thermopower exhibits an abrupt increase followed by a gradual decrease with gate voltage.

The observed behavior indicates an anti-parabolic DOS hybridized with a parabolic DOS.

Results enhance understanding of electronic states in transparent amorphous oxides.

Abstract

To clarify the electronic density of states (DOS) around the conduction band bottom for state of the art transparent amorphous oxide semiconductors (TAOSs), InGaZnO4 and In2MgO4, we fabricated TAOS-based transparent thin film transistors (TTFTs) and measured their gate voltage dependence of thermopower (S). TAOS-based TTFTs exhibit an unusual S behavior. The |S|-value abruptly increases, but then gradually decreases as Vg increases, clearly suggesting the anti-parabolic shaped DOS is hybridized with the original parabolic shaped DOS around the conduction band bottom.