HVPE GaN with low concentration of point defects for power electronics

We have studied photoluminescence (PL) from undoped GaN films grown by HVPE technique on sapphire. Several defect-related PL bands are observed in the low-temperature PL spectrum. The concentrations of the defects responsible for these PL bands are determined from the dependence of PL intensity on excitation intensity. The RL band with a maximum at 1.8 eV is often the dominant PL band in HVPE GaN. It is caused by an unknown defect with the concentration of up to ~10¹⁷ cm^-3. The concentrations of defects responsible for other defect- related PL bands rarely exceed 10¹⁵ cm^-3.