comparative study G.A. Lyubas, N.N. Ledentsov, D. Litvinov†, B.R. Semyagin, I.P. Soshnikov, V.M. Ustinov, V.V. Bolotov, D. Gerthsen† Institute of Semiconductor Physics, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia Ioffe Physicotechnical Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia † University of Karlsruhe, D-76128 Karlsruhe, Germany
Photoluminescence properties of type II GaAs / AsAs superlattics grown on (311) surface has been determined by its polarity. Earlier, using a high-resolution transmission electron microscopy (HRTEM) it was found that both GaAs / AlAs and AlAs / GaAs interfaces in superlattices grown on (311)A surface are corrugated with a height of 1 nm and a lateral periodicity of 3.2 nm. In the present work in HRTEM and Fourier transform images of superlattice grown on (311)B surface the 3.2 nm lateral periodicity is also revealed, however, it is ratner illegible because of not clear corrugating and due to the presence of longwavelength (> 10 nm) disorder. Photoluminescence spectra of GaAs / AlAs superlattice grown on (311)A surface are strongly polarized in relation to the direction of interface corrugation unlike the superlattice grown on (311)B surface, where corrugation was weak. We found that strong mixing between and X states in the conduction band took place only in the case of superlattices with strongly corrugated interfaces and allowed realization of brightred photoluminescence at room temperature at 650 nm. Observed differences between superlattices grown on (311)A and (311)B surfaces confirm that it is the interface currugation (not the crystallographic orientation) that plays a crucial role in optical properties of (311) superlattices.
5 Физика и техника полупроводников, 2002, том 36, вып.