Thickness dependence of exciton and polariton spectra from ZnSe films grown on GaAs substrates

Citation
Xj. Wang et al., Thickness dependence of exciton and polariton spectra from ZnSe films grown on GaAs substrates, J APPL PHYS, 90(12), 2001, pp. 6114-6119
Citations number
29
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
JOURNAL OF APPLIED PHYSICS
ISSN journal
0021-8979 → ACNP
Volume
90
Issue
12
Year of publication
2001
Pages
6114 - 6119
Database
ISI
SICI code
0021-8979(200112)90:12<6114:TDOEAP>2.0.ZU;2-0
Abstract
ZnSe films with thicknesses from 0.05 to 1.45 mum were grown on GaAs substr ates by molecular beam epitaxy. Low temperature photoluminescence (PL) and reflectance spectra are presented to show the thickness dependence of the e xciton and polariton properties in the films. In addition to sharp PL peaks from free and donor bound excitons, an acceptor bound exciton peak was obs erved in the thin films and its intensity decreases rapidly with the film t hickness. The PL characteristics show the acceptor centers being the defect states near the ZnSe/GaAs interface. The classical theory of exciton-polar itons was used to calculate the reflectance spectra and compared to the mea sured results. The comparison reveals the effects of strain, surface, and i nterface on the reflectance spectra from both heavy- and light-hole exciton s. In addition to the strain-induced light- and heavy-hole splitting, the l ight-hole excitons show a larger damping and less sensitivity to the surfac e dead layer than the heavy-hole excitons. When the film thickness increase s, the interference effects become more important and the contribution from the excited exciton states to the reflectance spectra may no longer be neg ligible. (C) 2001 American Institute of Physics.