Blueish green photoluminescence from nitrided GaAs 100/ surfaces

Optical and structural studies were made on the Si-doped 100.GaAs surfaces nitrided at a temperature between 6508 and 7508C for 15 min in the flowing NH3 gas. The wavelength of photoluminescence PL. spectra were observed to be shortened from 820 nm of the GaAs nitrided at 6508C with increasing nitridation temperature. Blueish green PL with wavelengths of approx. 490 nm and 470 nm were emitted from the nitrided surfaces at 7008 and 7508C, respectively. Results of AES and SIMS indicated that the surfaces are nitrided as GaAs1yxNx, 0-xF1.alloy layer, and the nitrided region also tended to increase as the temperature raised. High-resolution transmission electron microscopic HRTEM., transmission electron diffraction TED.and energy dispersive X-ray EDX.results showed that films peeled off from the nitrided surfaces consisted mainly of hexagonal, wurtzite-type gallium nitride GaN.with stacking faults and microtwins. q1999 Elsevier Science B.V. All rights reserved.