Substrate dependence on the growth of defective-wurtzite Al2S3 thin films using pulsed laser deposition

Wurtzite ferroelectrics such as AlScN have extensively studied in recent because they promise the compatibility to semiconductor technologies.These materials have higher remanent polarization than that of perovskite ferroelectrics, however its coercive field is very large comparing to them.Defective-wurtzite Al2S3 has been expected to have ferroelectricity with relatively low switching barrier comparing to AlN by a theoretical calculation.To evaluate experimentally its ferroelectric properties in the future, the deposition and growth of Al2S3 thin films and its dependences of various substrates were studied using pulsed laser deposition.It was demonstrated that Al2S3 can be grown epitaxially on a-Al2O3(0001) and SrTiO3(111) while Pt(111)/a-Al2O3(0001) is not applicable to the growth.