Transistor operation and mobility enhancement in top-gated LaAlO_3 / SrTiO_3 heterostructures

TL;DR

This paper demonstrates the operation of LaAlO_3 / SrTiO_3 top-gated transistors with high on-off ratios and shows that gating can increase electron mobility, offering insights for improved oxide electronics.

Contribution

It introduces LaAlO_3 / SrTiO_3 depletion mode top-gated transistors and reveals mobility enhancement through gating at low temperatures.

Findings

High on-off ratio (>1000) at room temperature

Mobility increases as carrier density decreases at low temperature

Systematic control of electron gas properties via top gating

Abstract

We report the operation of LaAlO_3 / SrTiO_3 depletion mode top-gated junction field-effect transistors using a range of LaAlO_3 thicknesses as the top gate insulator. Gated Hall bars show near ideal transistor characteristics at room temperature with on-off ratios greater than 1000. Lower temperature measurements demonstrate a systematic increase in the Hall mobility as the sheet carrier density in the channel is depleted via the top gate, providing a route to higher mobility, lower density electron gases in this system.