Thermal stability of GaN investigated by lowhyphen;temperature photoluminescence spectroscopy

摘要

We have studied the thermal behavior of 1hyphen;mgr;mhyphen;thick GaN films grown by plasmahyphen;enhanced molecular beam epitaxy. Samples were annealed at elevated temperatures in a nitrogen environment and were characterized by lowhyphen;temperature photoluminescence (PL). After GaN samples were annealed at up to 700thinsp;deg;C, the freehyphen;exciton transition PL line intensity improved. This PL line intensity degraded when annealing temperatures reached 900thinsp;deg;C. After annealing at 900thinsp;deg;C, GaN samples with inferior crystalline quality exhibited a line at 2.3 eV attributed to point defects and antisite defects.