Electrical transport across Au/Nb:SrTiO3 Schottky interface with different Nb doping

TL;DR

This study investigates electron transport in Nb-doped SrTiO3 crystals with different doping levels, analyzing resistivity, mobility, and Schottky interface behavior to inform oxide-semiconductor device design.

Contribution

It provides a comparative analysis of transport mechanisms in low and high Nb-doped SrTiO3, highlighting the transition from thermionic emission to deviation at higher doping levels.

Findings

Resistivity and mobility are temperature dependent, carrier concentration is nearly temperature invariant.

Thermionic emission dominates in low doped samples, deviates in high doped samples.

Transport behavior varies significantly with doping density.

Abstract

We have investigated electron transport in Nb doped SrTiO$_3$ single crystals for two doping densities. We find that the resistivity and mobility are temperature dependent in both whereas the carrier concentration is almost temperature invariant. We rationalize this using the hydrogenic theory for shallow donors. Further, we probe electrical transport across Schottky interfaces of Au on TiO$_2$ terminated n-type SrTiO$_3$. Quantitative analysis of macroscopic I-V measurements reveal thermionic emission dominated transport for the low doped substrate whereas it deviates from such behavior for the high doped substrate. This work is relevant for designing devices to study electronic transport using oxide-semiconductors.