Enhancement of compositional modulation in GaInP epilayers by the additionof surfactants during organometallic vapor phase epitaxy growth

Citation
Rt. Lee et al., Enhancement of compositional modulation in GaInP epilayers by the additionof surfactants during organometallic vapor phase epitaxy growth, J CRYST GR, 233(3), 2001, pp. 490-502
Citations number
34
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
JOURNAL OF CRYSTAL GROWTH
ISSN journal
0022-0248 → ACNP
Volume
233
Issue
3
Year of publication
2001
Pages
490 - 502
Database
ISI
SICI code
0022-0248(200112)233:3<490:EOCMIG>2.0.ZU;2-V
Abstract
The use of surfactants in semiconductors during organometallic vapor phase epitaxy (OMVPE) is a powerful and exciting tool for controlling the propert ies of epilayers. The effects of the isoelectronic surfactants Sb and Bi ha ve been systematically studied for GaInP alloys grown lattice-matched to Ga As substrates by OMVPE. Addition of small concentrations of either Sb or Bi leads to the elimination of the CuPt-B ordering observed in undoped layers , At high Sb concentrations, additional changes in the structure and optica l properties are observed. The layers spontaneously form a structure with a lateral compositional modulation in the [I 10] direction. Surface undulati ons are clearly seen by atomic force microscopy (AFM) for the layers with c ompositional modulation. The low temperature photoluminescence (PL) peak en ergy is observed to decrease with increasing compositional modulation. The PL emission is strongly anisotropic, with a high intensity in the [I 10] di rection which is the reverse of the polarization observed for CuPt ordered GaInP layers. Compositional modulation and surface undulation are found to be strongly affected by the growth rate. The amplitude of the compositional modulation in GaInP layers grown with either surfactant is significantly i ncreased for decreased growth rates. The process controlling the amplitude appears to be kinetically limited. It is likely that adding the surfactant Sb or Bi increases the ad-atom surface diffusion coefficients which acts to enhance the extent of compositional modulation in GaInP especially when gr own at low rates. (C) 2001 Elsevier Science B.V. All rights reserved.