Formation Of Beta-Be3n2 Nanocrystallites In Be-Implanted Gan

A small Be ion dose of 5 x 10(14) cm(-2) was implanted in a 2 mu m thick GaN epilayer at an energy of 50 keV. The sample was characterized by high-resolution transmission electron microscopy (HRTEM) and Raman spectroscopy techniques after a post-implantation rapid thermal annealing (RTA) treatment. The HRTEM images show the crystallographic (1 1 0) and (0 0 2) planes of beta-Be3N2. Two characteristic parallelograms drawn in Fast Fourier transform (FFT) image support the formation of beta-Be3N2 nanocrystallites in RTA treated sample. Two Raman peaks at 168 and 199 cm(-1) are observed in the Raman spectrum of the sample that are assigned to beta-Be3N2 on the basis of group theory and HRTEM data. The Raman peak at 168 cm(-1) is found close to the K point in the first Brillouin zone of beta-Be3N2 while the peak at 199 cm(-1) is assigned as a combination mode of the fundamental Raman modes of beta-Be3N2.