Electric-Field-Controlled Phase Transformation in WO3 Thin Films through Hydrogen Evolution

Abstract

Field-effect transistors with ionic-liquid gating (ILG) have been widely employed and have led to numerous intriguing phenomena in the last decade, due to the associated excellent carrier-density tunability. However, the role of the electrochemical effect during ILG has become a heavily debated topic recently. Herein, using ILG, a field-induced insulator-to-metal transition is achieved in WO₃ thin films with the emergence of structural transformations of the whole films. The subsequent secondary-ion mass spectrometry study provides solid evidence that electrochemically driven hydrogen evolution dominates the discovered electrical and structural transformation through surface absorption and bulk intercalation.

Using ionic-liquid gating, a field-induced insulator-to-metal transition is achieved in WO₃ thin films with the emergence of structural transformations of the whole films. Subsequent secondary-ion mass spectrometry provides solid evidence that electrochemically driven hydrogen evolution dominates the discovered electrical and structural transformation through surface absorption and bulk intercalation.

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