Buffer layered growth of nickeline and zinc-blende MnTe on c-plane Al­₂O₃

MnTe is a well-known polymorphic semiconductor with nickeline, zinc blende and wurtzite being its most widely studied phases. While nickeline MnTe has found application in dilute magnetic semiconductors and thermoelectric materials, the zinc blende and wurtzite phases are utilized in optoelectronic devices owing to their larger bandgap. So far, these films have been grown on structurally compatible substrates, via doping or by displacive transformation. We have successfully grown both nickeline and zinc blende phases on c-plane Al­₂O₃ substrates by developing different buffer layer for the two phases. Such control over growth of MnTe could potentially lead to novel heterostructures and provide new directions for fabrication of devices. It is also particularly beneficial from the point of view of growing thin films of Mn based magnetic topological insulators.