Structural, optical, and electrical characteristics of 70 Mev Si⁵⁺ ion irradiation-induced nanoclusters of gallium nitride

We report the formation of nanoclusters on the surface of gallium nitride (GaN) epilayers due to irradiation with 70 MeV Si ions with the fluences of 1 × 10¹² ions/cm² at the liquid nitrogen temperature (77 K). GaN epilayers were grown using a metal organic chemical vapor deposition system. Omega scan rocking curves of (002) and (101) plane reflection shows irradiation-induced broadening. Atomic force microscopy imagery revealed the formation of nanoclusters on the surface of the irradiated samples. X-ray photoelectron spectroscopy confirms that the surface features are composed of GaN. The effects of ion-beam-produced lattice defects on the surface, electrical, and optical properties of GaN were studied and possible mechanisms responsible for the formation of nanoclusters during irradiation have been discussed.