Growth of GaN Single-Crystal Boules.

The first step in growing a GaN boule was to demonstrate the possibility of growing GaN from elemental Ga and ammonia on a substrate. Although GaN crystals were obtained the diffusion rate of gas vapor was too high. A number of other problems was uncovered and their solution was conceived. Several changes to the deposition system were made, but to succeed, a more radical redesign is needed. This new design will be proposed as a first task during Phase II. The Phase I work has been a very useful experience that uncovered valuable insights. jg