Structure and optical anisotropy of vertically correlated submonolayer InAs/GaAs quantum dots

Abstract

A vertically correlated submonolayer (VCSML) InAs/GaAs quantum-dot (QD) heterostructure was studied using transmission electron microscopy, high-resolution x-ray diffraction (HRXRD) and polarization-dependent photoluminescence. The HRXRD (004) rocking curve was simulated using the Tagaki–Taupin equations. Excellent agreement between the experimental curve and the simulation is achieved assuming that indium-rich VCSML QDs are embedded in a quantum well (QW) with lower indium content and an observed QD coverage of 10%. In the VCSML QDs, the vertical lattice mismatch of the InAs monolayer with respect to GaAs is around 1.4%, while the lattice mismatch in the QW is negligible. The photoluminescence is transverse magnetic—polarized in the edge geometry.