Sputter deposition and thermal evaporation of Li2O, Li2S, and Li2Se films

Thin layers containing lithium oxide (Li2O), lithium sulfide (Li2S), or lithium selenide (Li2Se) are relevant for many electrochemical processes in lithium-based batteries. As a step toward understanding the electrochemical properties of such layers, this work demonstrates the growth of dense single-phase films by both sputter deposition (for Li2O and Li2S) and thermal evaporation (for Li2S and Li2Se). The dependence of morphology and grain size on the growth conditions is characterized. Reactive deposition is found to be faster and more practical than direct deposition, and both sputtered S8 and heated SnS2 are shown to be viable sulfur precursors for growing sulfides. These results enable the preparation of Li2O, Li2S, and Li2Se films suitable for future electrochemical studies. An initial set of conductivity data from an evaporated Li2S film is also presented.