Decomposition behavior of GaN under solid and ambient N2 pressure

Abstract

We investigated the decomposition behavior of GaN crystals under high N2 and solid pressures using a belt-type high-pressure apparatus. The decomposition curve of GaN under solid pressure showed a considerably moderate increase compared to that under a N2 pressure. Such difference was attributed to the N2 dissolution in the Ga melt, where a high N2 pressure creates a supersaturated GaN state, which effectively prevent its decomposition. Conversely, under a solid pressure, the increase in the GaN decomposition temperature followed a common change in enthalpy, which is consistent with its typical thermodynamic behavior. The decomposition behavior of GaN under a solid pressure demonstrated its successful high-temperature annealing using a belt-type high-pressure apparatus. Therefore, this study provides valuable insights into the thermodynamic stability of GaN under different pressures, which is critical for optimizing high-performance GaN-based devices.