Gallium Nitride

Gallium nitride (GaN) is a wide bandgap semiconductor which has rapidly transformed the world by enabling energy-efficient white light-emitting diodes and promising energy-efficient power electronic devices. Bulk crystal growth is actively being researched to enable inexpensive large-area substrates. Currently, bulk GaN substrates are commercially available using the hydride vapor phase epitaxy method, but they lack high structural quality and availability of arbitrarily oriented substrate orientations. The ammonothermal and sodium flux methods are the two most promising true bulk crystal growth techniques being explored to fill this void and enable large-area, arbitrarily oriented, low-cost substrates of high structural quality. While challenges remain for all three growth methods, considerable progress has occurred over the years. This chapter provides an overview of the three growth methods and current characteristics of state-of-the-art material after a brief introduction to GaN and general challenges for bulk GaN growth. (Read full text)