Optical study of heterointerface configuration in narrow GaAs/AlGaAs single quantum wells prepared with growth interruption

• Published in: Journal of Applied Physics
• Main Authors: Yuan, Z. L., Xu, Z. Y., Zheng, B. Z., Luo, C. P., Xu, J. Z., Ge, Weikun, Zhang, P. H., Yang, X. P.
• Format: Article in Journal/Newspaper
• Language: English
• Published: AIP Publishing 1996
• Subjects: General Physics and Astronomy; Smooth Island
• Online Access: http://dx.doi.org/10.1063/1.360896; https://pubs.aip.org/aip/jap/article-pdf/79/2/1073/8047652/1073_1_online.pdf

Photoluminescence and time-resolved photoluminescence were used to study the heterointerface configuration in GaAs/AlGaAs quantum wells grown by molecular-beam epitaxy with growth interruption. Photoluminescence spectra of the growth-interrupted sample are characterized by multiplet structures, with energy separation corresponding to a 0.8 monolayer difference in well width, rather than 1 monolayer as expected from the ‘‘atomically smooth island’’ picture. By analyzing the thermal transfer process of the photogenerated carriers and luminescence decay process, we further exploit the exciton localization at the interface microroughness superimposed on the extended growth islands. The lateral size of the microroughness in our sample was estimated to be 5 nm, less than the exciton diameter of 15 nm. Our results strongly support the bimodal roughness model proposed by Warwick et al. [Appl. Phys. Lett. 56, 2666 (1990)].