Extremely small trap concentrations in high-purity n-type GaN grown by quartz-free hydride vapor phase epitaxy

Trap characterization was performed for n-type GaN grown by the quartz-free hydride vapor phase epitaxy method with a newly developed reactor. Deep-level transient spectroscopy revealed several electron and hole traps within 1 eV of the conduction and valence band edges. All were present at low concentrations (∼5 × 1013 cm−3). The concentrations of other traps near the mid-gap region were estimated to be below 1 × 1013 cm−3 for donor-type traps and below 5 × 1013 cm−3 for acceptor-type traps. These results demonstrate that the new reactor enables the growth of high-purity GaN with extremely small trap concentrations.