Crystallization of amorphous InAs/GaAs films on GaAs

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(1 1 3)A substrates. Growth is elaborated on the plane GaAs(0 0 1) and then applied to the patterned GaAs(1 1 3)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(1 1 3)A overgrown with (In,Ga)As attest to the formation of wire-like structures.