Potentiostatic Electrodeposition and Characterizations of Tin Selenide (SnSe) Films on Gold

We report a study of the potentiostatic electrodeposition on gold of SnSe, where Sn(II) and Se(IV) were used as precursors and sodium oxalate as a complexing agent. In order to investigate the behavior of the electrochemical system on gold, cyclic voltametric (CV) experiments were first carried out. A narrow potential window, between -0.5 and -0.6 V vs Ag/AgCl (KCl sat.) was then defined as being suitable for thin film deposition. Textured [011] and [111] polycrystalline SnSe films were obtained with a faradaic yield up to 75%. In addition, the unexpected presence of AuSn alloy was identified during the electrodeposition process, depending on the selected growth potential, both by CVs and X-Ray diffraction measurements. Finally, the estimation of the fundamental band gap, i.e., the indirect transition from α-E curves of SnSe films of different thicknesses, provides a signature mean value of 0.7 eV.