Suppression of vacancy aggregation by silicon-doping in low-temperature-grown Ga_1−xCr_xN

Effect of Si doping on low-temperature grown GaCrN films has been investigated by positron annihilation spectroscopy. In undoped GaCrN films grown at $540 °C$⁠, vacancy clusters with sizes of V₆–V₁₂ were found to be responsible for positron trapping. Such vacancy clusters were considerably suppressed in Si-doped GaCrN films grown at $540 °C$⁠, although divacancies (⁠$VGaVN$⁠) still survived. The Si-doping may be one possible way to suppress vacancy aggregation during low temperature crystal growth, and the further methods to remove divacancies are required.