Cathodoluminescence Study on Thermal Recovery Process of Mg‐Ion Implanted N‐Polar GaN

Abstract

Thermal recovery of N‐polar GaN(000) samples implanted with magnesium and hydrogen ions was investigated by cathodoluminescence (CL) spectroscopy. The high thermal stability of N‐polar GaN allowed annealing process over 1200 °C without protective overlayer. The CL emissions from acceptor‐bound excitons and donor‐bound excitons were observed in the near‐band‐edge (NBE) after annealing over 1000 °C of the ion implanted samples, which indicates the formation of Mg acceptors. The emission intensities both in the NBE and in the green luminescence (GL) band increased with the annealing temperature, resulting from reducing the non‐radiative recombination centers. On the other hand, the enhancement of the GL band (nitrogen vacancy complexes) by prolonging the annealing duration above 1200 °C was not significant as compared to the band‐edge emission, probably resulting from the enhancement of activating the implanted Mg ions. These results give clear directions to improve the quality of Mg‐ion implanted GaN.