Thermal shock–induced oxygen vacancy engineering in metal oxide electronics

Abstract

Thermal shock is typically considered a detrimental phenomenon that should be avoided in material processing due to its potential to induce structural failure. Contrary to this conventional understanding, we report for the first time that the electrical conductivity of indium tin oxide (ITO) thin films can be dramatically enhanced within a few seconds by a controlled thermal shock process. Systematic characterization revealed that this rapid conductivity enhancement originates from an increase in carrier concentration, induced by the formation of intrinsic dopants—oxygen vacancies. Optical bandgap widening (Burstein–Moss shift), reduction in the Seebeck coefficient, and X-ray photoelectron spectroscopy analyses consistently verified a substantial rise in carrier density after thermal shock. The underlying mechanism is attributed to the release of elastic energy within the ITO lattice during thermal shock, which loosens In–O bonds and reduces the activation energy for oxygen vacancy formation by approximately 10⁻¹² J. This study demonstrates that thermal shock can serve as an energy-efficient and ultrafast post-treatment technique to tailor carrier concentration and electrical conductivity in transparent conductive oxides, offering a new paradigm in oxide semiconductor processing.