Impact of V/III ratio on electrical properties of GaN thick films grown by hydride vapor-phase epitaxy

TLDR: In this paper, the impact of V/III ratio on electrical properties of GaN thick films is investigated, which are grown by hydride vapor-phase epitaxy, and it is shown that the electron concentration decreases with the increase of V /III ratio, while their electrical resistivity and electron mobility increase simultaneously.

Abstract: Impact of V/III ratio on electrical properties of GaN thick films are investigated, which are grown by hydride vapor-phase epitaxy. The authors note that the electron concentration of GaN films decreases with the increase of V/III ratio, while their electrical resistivity and electron mobility increase simultaneously. These indicate that enhancing V/III ratio suppresses electron-feeding sources in GaN films, which is not by generating electron-trapping centers but by reducing donor-type defects. On the other hand, it is shown that the linewidth of x-ray rocking curves in GaN films decreases and the near-band edge emission intensity of 10K photoluminescence spectra increases as V/III ratio increases. These mean that higher V/III ratio condition helps for reducing crystalline point defects in GaN films. In terms of theoretical fitting into the temperature-dependence curves of electron mobilities, it is found that the electron transport of GaN films grown in lower V/III ratio condition is more hampered by de...