Gas-source molecular beam epitaxial growth, characterization, and light-emitting diode application of InxGa1-xP on GaP(100)

Highly lattice-mismatched In,Ga,+P (~~0.38) layers were grown on GaP substrates by gas-source molecular beam epitaxy. A relatively thin, compositionally linear-graded buffer layer was used to reduce the number of threading dislocations. Studies by double-crystal x-ray diffraction and transmission electron microscopy show this buffer layer to be 97% strain-relaxed along both (110) directions with dislocations well confined within the graded buffer and the substrate. Threading dislocation densities in the top layers were less than 1X lo7 cm-‘. Room-temperature photoluminescence, ranging from 560 to 600 nm, is achieved. Heterojunction p-i-n diodes emitting at 560 nm at 300 K exhibit good rectifying and reverse breakdown characteristics.