MOVPE Growth Window for High-Nitrogen GaAsN Alloy Films for Long Wavelength Emission
The high quality GaAsN epitaxial films with the typical thickness of 150-200 nm and the N contents up to 5.5% were grown by MOVPE. The maximum N content of 2.75% at the growth temperature of 550 oC was enhanced to 5.1% at 500 oC and 5.5% at 450 oC. The lower growth temperature may efficiently suppress desorption of N atoms from the growing surface. The narrow high-resolution X-ray diffraction peaks and the clear Pendellösung fringes indicate that the GaAsN films with high uniformity and fairly flat interface were obtained. The 6K-photoluminescence (PL) peak energy of the GaAsN films was varied from 1.38 eV to 1.01 eV with increasing N content up to 2.75%, but no near-band-edge emission was observed in the higher-N-content films, indicating the increase of nonradiative recombination centers caused by the N-related lattice imperfections. Besides, after post growth thermal annealing at 650 oC for 2 min, PL spectrum shows that the near-band-edge emission as low as 0.97 eV (1.3 μm) have been achieved with the film of 5.1% N.
S. J. CHUA, J. H. TENG, O. WADA, R. DE LA RUE and X. H. TANG
S. Sanorpim et al., " MOVPE Growth Window for High-Nitrogen GaAsN Alloy Films for Long Wavelength Emission", Advanced Materials Research, Vol. 31, pp. 218-220, 2008