Electric field thermopower modulation analysis of an interfacial conducting layer formed between Y2O3 and rutile TiO2

TL;DR

This study uses electric field modulation of thermopower to analyze carrier transport in a bilayer structure of TiO2 and a thin interfacial layer, revealing contributions from both layers and confirming the interfacial layer's thickness.

Contribution

It demonstrates that electric field modulation of thermopower effectively characterizes carrier transport properties of ultrathin interfacial layers in bilayer structures.

Findings

Both rutile TiO2 and the interfacial layer contribute to carrier transport.

The interfacial layer has a mobility of ~0.3 cm2V-1s-1.

The interfacial layer thickness is below ~3 nm, consistent with TEM observations.

Abstract

Electric field modulation analysis of thermopower (S) - carrier concentration (n) relation of a bilayer laminate structure composed of a 1.5-nm thick conducting layer, probably TinO2n-1 (n=2, 3,...) Magn\'eli phase, and rutile TiO2 was performed. The results clearly showed that both the rutile TiO2 and the thin interfacial layer contribute to carrier transport: the rutile TiO2 bulk region (mobility mu~0.03 cm2V-1s-1) and the 1.5-nm thick interfacial layer (mu~0.3 cm2V-1s-1). The effective thickness of the interfacial layer, which was obtained from the S-n relation, was below ~ 3 nm, which agrees well with that of the TEM observation (~1.5 nm), clearly showing that electric field modulation measurement of S-n relation can effectively clarify the carrier transport properties of a bilayer laminate structure.