Crystallization of amorphous InAs/GaAs films on GaAs

Abstract

A novel route based on the structural transition from amorphously deposited material to epitaxial films via thermally induced crystallization is probed for wire formation at side-walls of shallow ridges on patterned GaAs(113)A substrates. Growth is elaborated on the plane GaAs(001) and then applied to the patterned GaAs(113)A substrates. Amorphous layers of InAs and GaAs are deposited by migration-enhanced epitaxy at a growth temperature of Tg=100°C. Annealing at temperatures between 450 and 550°C transforms these films into crystalline state. The reported technique facilitates the growth of (In,Ga)As-QWs with high In content and very low interface roughness. Despite strong non-equilibrium conditions during low-temperature deposition, efficient photoluminescence emission is obtained, which is further enhanced by post-growth rapid thermal annealing, concomitant with a controllable spectral blue-shift. The characterization of patterned GaAs(113)A overgrown with (In,Ga)As attest to the formation of wire-like structures.