Anisotropic surface segregation of indium atoms in molecular beam epitaxy of InGaAs/GaAs quantum wells

In order to investigate the dependence of indium surface segregation on ste p structures, InGaAs (InAs)/GaAs quantum wells (QWs) were grown by molecula r beam epitaxy on vicinal GaAs(001) substrates, misoriented toward [011] an d [0(1) over bar1] directions. High energy shift and narrow linewidth of ph otoluminescence spectra were observed for InAs QWs prepared on the [011]-st epped surface. By cross-sectional transmission electron microscope observat ion, it was found that broadening of InGaAs QWs was enhanced on the [011]-s tepped surface. These phenomena were explained by the anisotropic segregati on effect due to the difference in the step structure between the [011] ste p and the [0(1) over bar1] step. (C) 2001 American Institute of Physics.