Controlling factors of GaN wear

The optoelectronic properties of gallium nitride (GaN) have been well studied for decades, with results being translated to applications in solid state lighting and lasers, thermoelectricity, solar cells, power electronics, etc. However, the mechanical and tribological properties of GaN have been studied and understood far less than its optoelectronic properties. Our research aims to explore the wear performance of GaN and the controlling factors that will affect its wear rate. Directionality of GaN wear rate was observed with 60° periodicity. The local highest wear rate appeared along '1210' while the local lowest wear rate appeared along '1100'. The experimental results revealed that, the wear rate of GaN increased over 30 times when the testing environment changed from low humidity air to high humidity lab air. AES and SEM/EDS were employed to analyze the surface chemistry inside and outside the wear scar. The results provided further insight into the tribochemistry of GaN wear against alumina under different humidity environments.