Molecular beam epitaxy of GaSb0.5As0.5 and AlxGa1−xSbyAs1−y lattice matched to InP

Abstract
Single crystal films of GaSby As1−y and Alx Ga1−x Sby As1−y alloys having compositions within the miscibility gap can be prepared using nonequilibrium growth techniques. We have successfully grown these alloys lattice matched to InP by molecular beam epitaxy. Transmission electron microscopy studies of these alloys grown on (100) InP at 500–560 °C show evidence of compositional modulation due to spinodal decomposition similar to that of InGaAsP grown by vapor phase epitaxy on InP used for laser diodes emitting at ∼1.5 μm. From the studies of optical microscopy, x-ray diffraction, and photoluminescence measurements at both room temperature and liquid helium temperature, these epitaxial layers are considered of high quality for optoelectronic device applications in the wavelength range of 0.65–1.7 μm lattice matched to InP substrates.