EFFECTS OF SUBSTRATE-TEMPERATURE AND V III FLUX RATIO ON THE GROWTH OF INALAS ON INP SUBSTRATES BY MOLECULAR-BEAM EPITAXY/

Molecular beam epitaxial growth of In0.52Al0.48As epilayers on InP(100 ) substrates at a wide range of substrate temperatures (470-550 degree s C) and at arsenic overpressures (V/III ratio) which are higher than previously reported [4] is carried out. Analysis performed using low t emperature photoluminescence (PL) showed a strong dependence of the ph otoluminescence (PL) linewidth on the substrate temperature. Correspon ding X-ray diffraction measurements showed the lowest lattice-mismatch between the In0.52Al0.48As epilayer and InP substrate to occur at the substrate temperature at which the lowest PL linewidth was achieved. However, within the range of V/III flux ratios investigated (32 to 266 ), narrow PL linewidths of less than 20 meV were measured, and the lin ewidths tend to be generally narrower at flux ratios greater than 150. The lowest value of 14 meV was recorded for the samples gown at a V/I II ratio of 160. The lattice-mismatch between the epilayer and the sub strate for these samples was also found to be relatively insensitive t owards changes in the V/III flux ratios.