Temperature dependent lattice constant of Al0.90Ga0.10AsySb1−y

Abstract

Using x-ray diffraction, the in-plane and out-of-plane lattice constants of Al0.90Ga0.10AsySb1−y epilayers grown on GaSb and GaAs substrates were determined between 30 and 398 °C for y=0.003–0.059. The bulk lattice constant was then calculated from the in-plane and out-of-plane lattice constants. A polynomial function for the bulk lattice constant as a function of y and temperature was derived from a fit to the resulting data. Comparison to measured out-of-plane lattice constants of platinum-coated Al0.90Ga0.10AsySb1−y indicates that the polynomial function is valid up to around 550 °C. The polynomial function can be used to determine the lattice matching of Al0.90Ga0.10AsySb1−y to, e.g., GaSb at typical growth temperatures used for growth of cladding layers in laser structures. A formula is given for calculating the As mole fraction for lattice matching to GaSb at a given temperature.