A method of forming a semiconductor structure includes providing a substrate comprising a first material portion and a single crystal silicon layer on the first material portion. The substrate further comprises a major front surface, a major backside surface opposing the major front surface, and a plurality of grooves positioned in the major front surface. A buffer layer is deposited in one or more of the plurality of grooves. A semiconductor material is epitaxially grown over the buffer layer and in the one or more plurality of grooves, the epitaxially grown semiconductor material comprising a hexagonal crystalline phase layer and a cubic crystalline phase structure disposed over the hexagonal crystalline phase.