Layered boron nitride as a release layer for mechanical transfer of GaN-based devices

We demonstrate that hexagonal boron nitride (h-BN) can work as a release layer that enables the mechanical transfer of gallium nitride (GaN)-based device structures onto foreign substrates. We illustrate the potential versatility of this approach by growing an AlGaN/GaN heterostructure, an InGaN/GaN multiple-quantum-well (MQW) structure, and a multiple-quantum-well light-emitting diode on h-BN-buffered sapphire substrates. These device structures, ranging in area from five millimeters square to two centimeters square, are then mechanically released from the sapphire substrates and successfully transferred onto other substrates.