LATERAL VARIATION OF QUANTUM-WELL CONFINEMENT ENERGY IN TRIANGULAR-SHAPED DOT-LIKE STRUCTURES GROWN BY MOLECULAR-BEAM EPITAXY ON PATTERNED GAAS (311)A SUBSTRATES

Highly ordered triangular-shaped dot-like (TD) structures are grown by molecular beam epitaxy (MBE) on patterned GaAs (311)A substrates and imaged by atomic force microscopy (AFM). The lateral variation of the quantum-well (QW) confinement energy in the TD structures is revealed by low-temperature cathodoluminescence (CL) and micro-photoluminescenc e (In-PL) spectroscopy. The CL emission centered at 783 nm, 772 nm and 767 nm correspond to three distinct regions of the TD structure ident ifying lateral energy barriers around the top portion of the TD struct ure induced by variations of the QW width. The mu-PL spectra further s how well-resolved peaks originating from the three portions of the TD structure indicating a lateral energy barrier of 13 meV between the to p portion and the nearby smooth regions with efficient radiative recom bination.