Comparison of hexagonal ZnS film properties on c- and a-sapphires

Abstract Wurtzite ZnS films were epitaxially grown on c - and a -plane sapphire substrates at 800°C by pulsed laser deposition using a KrF excimer laser. Hexagonal phase was distinguished from cubic phase by detailed X-ray diffraction analysis. Unlike a typical epitaxial relationship such as GaN or ZnO on sapphire, the wurtzite ZnS films on c - and a -sapphire showed unique epitaxial relationships of Al 2 O 3 [1 1 2 0] ∥W-ZnS [1 1 2 0] and Al 2 O 3 [0 0 0 1]∥W-ZnS [1 0 1 0] , respectively. Multi-domains were observed in wurtzite ZnS films on a -sapphire. Both films on sapphire exhibited strong excitonic absorption at room temperature.