A Broad-spectrum Gas Sensor based on Correlated Two-Dimensional Electron Gas

Abstract

Designing a broad-spectrum gas sensor capable of identifying gas components in complex environments, such as mixed atmospheres or extreme temperatures, is a significant concern for various technologies, including energy, geological science, and planetary exploration. The main challenge lies in finding materials that exhibit high chemical stability and wide working temperature range. Materials that amplify signals through non-chemical methods could open up new sensing avenues. Here, we present the discovery of a broad-spectrum gas sensor utilizing correlated two-dimensional gas (C-2DEG) at a delta-doped LaAlO3/SrTiO3 interface with LaFeO3. Our study revealed that a back-gating on this 2DEG can induce a non-volatile metal to insulator transition, which consequently can activate the 2DEG to sensitively and quantitatively probe very broad gas species, no matter whether these are polar, non-polar, or inert gases. Such C-2DEG sensor remains stable in almost any atmosphere within a wide temperature range, and its readout is a simple measurement of electric resistance change, thus providing a very low-cost and high-efficient sensing technique.