Real-time observation of atomic ordering in (001) In0.53Ga0.47As epitaxial layers.

Abstract

We report the first real-time observation of atomic ordering in a semiconductor alloy during epitaxial growth. (001) ${\mathrm{In}}_{0.53}{\mathrm{Ga}}_{0.47}$As layers deposited below about 400 \ifmmode^\circ\else\textdegree\fi{}C exhibit a strong anisotropy in the broadening parameters of the ${E}_{1}{,E}_{1}+{\ensuremath{\Delta}}_{1}$ transitions that is observable with reflectance-difference spectroscopy. This unusual optical behavior results from intraband mixing driven by triple-period ordering along both [111] and $[11\overline{1}]$ directions simultaneously. This microstructure is realizable with stoichiometry ${\mathrm{In}}_{0.556}{\mathrm{Ga}}_{0.444}\mathrm{As}$ virtually identical to that needed to lattice match InP.