OPTICAL AND STRUCTURAL CHARACTERIZATIONS FOR OPTIMIZED GROWTH OF IN0.52AL0.48AS ON INP SUBSTRATES BY MOLECULAR-BEAM EPITAXY

Citation
Sf. Yoon et al., OPTICAL AND STRUCTURAL CHARACTERIZATIONS FOR OPTIMIZED GROWTH OF IN0.52AL0.48AS ON INP SUBSTRATES BY MOLECULAR-BEAM EPITAXY, Materials science & engineering. B, Solid-state materials for advanced technology, 35(1-3), 1995, pp. 109-116
Citations number
20
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Material Science","Physics, Condensed Matter
ISSN journal
0921-5107
Volume
35
Issue
1-3
Year of publication
1995
Pages
109 - 116
Database
ISI
SICI code
0921-5107(1995)35:1-3<109:OASCFO>2.0.ZU;2-O
Abstract
Growth of In0.52Al0.48As epilayers on InP(100) substrates by molecular beam epitaxy at a wide range of substrate temperatures (470-550 degre es C) and at high arsenic beam equivalent pressures is carried out. An alysis performed using low-temperature photoluminescence (PL) and doub le axis X-ray diffraction (XRD) showed a strong dependence of the PL a nd XRD linewidths and lattice-mismatch on the substrate temperature, w ith minimum linewidths and lattice-mismatch occurring between approxim ately 500 and 520 degrees C. The XRD intensity ratio (Int(epi)/Int(sub )) varied in opposition to the lattice-mismatch, with higher intensity ratios corresponding to lower lattice-mismatches. From the X-ray diff raction curves of samples grown at low temperatures, it was observed t hat the main peak associated with the InAlAs epilayer is comprised of smaller peaks, which strongly indicates disordering owing to the prese nce of alloy clustering. PL spectrum taken at increasing temperatures showed the quenching of the main emission peak followed by the evoluti on of a distinct peak at lower energy, possibly associated with carrie r localization due to the presence of lattice disorder. In addition to the InAs-like and AlAs-like longitudinal-optic (LO) phonon modes at 2 34 cm(-1) and 370 cm(-1), respectively, Raman scattering measurements also showed an additional higher energy mode at 273 cm(-1) in the samp les grown at lower temperatures approaching 470 degrees C. Within the range of V/III flux ratios investigated (32-266), the lowest PL linewi dth of 14 meV was recorded for the samples grown at a V/III ratio of 1 60 at a substrate temperature of 510 degrees C. The lattice-mismatch b etween the epilayer and the substrate for these samples was also found to be relatively insensitive to changes in the V/III flux ratios.