Tilted domain growth of metalorganic chemical vapor (MOCVD)-grown ZnO(0001) on α-Al2O3(0001)

Abstract

ZnO grown on α-Al2O3(0001) generally possesses an orientation such that α-Al2O3(0001) is parallel to ZnO(0001) and two in-plane domains nucleate, so that α-Al2O3[11¯20] is parallel to ZnO[11¯20] and/or α-Al2O3[11¯20] is parallel to ZnO[10¯10]. In this paper, we report a new growth mode for ZnO grown on α-Al2O3(0001) using metalorganic chemical vapor deposition (MOCVD). We find that α-Al2O3[11¯20] is parallel to ZnO[10¯10], but the (0001) plane of ZnO is tilted relative to the (0001) plane of α-Al2O3 such that ZnO(0001) is almost parallel to the α-Al2O3(¯1104) plane. This orientation reduces the extent of lattice mismatch. The interface between ZnO and α-Al2O3 is abrupt and possesses periodic dislocations.