Electrochemical deposition of GaTe thin films for photoelectrochemical applications

GaTe thin films are electrochemically deposited on indium tin oxide for photoelectrochemical applications. The electrochemical deposition behavior of GaTe thin films in acidic solution of HTeO2+ with Ga3+ is studied with cyclic voltammetry combining with operando transmittance spectroscopy. Underpotential deposition of Ga on Te starts at potential of − 0.35 V. The presence of Ga3+ in the solution can strongly suppressed the formation of H2Te. XPS analysis reveals that Ga-rich GaTe is deposited over a wide potential range. The photoelectrochemical performance of the thin films as photocathodes is strongly dependent on the deposition potential. The GaTe films deposited at − 1.0 V produced the highest photocurrent of about − 0.03 mA cm−2. Meanwhile the film deposited at − 0.35 V shows improved performance during photoelectrochemical measurement, which can be ascribed to the increased GaTe content during photoelectrochemical measurements, as confirmed by XPS analysis.