Effect of growth temperature on surface morphology and optical properties of undoped Al0.32Ga0.68As

Abstract

Undoped Al0.32Ga0.68As material which was grown by metal-organic chemical vapor deposition at different growth temperature. The evolution mechanism of surface morphology of Al0.32Ga0.68As was explained by the variation of step growth direction and growth rate, which were affected by growth temperature. Electrochemical capacitance-voltage results showed the dependence of conductivity type on carbon incorporation. Al0.32Ga0.68As changed from p-type to n-type conductivity and carrier concentration decreased as growth temperature increased from 640 °C to 740 °C. The disorder of Al0.32Ga0.68As ternary alloy originated from its structural defects, which were attributed to aluminum (Al) compositional fluctuations by the incorporation of carbon impurity. The crystal quality of undoped Al0.32Ga0.68As was characterized by the intensity of Fermi-edge singularity peak. The change rule of the intensity of Al0.32Ga0.68As and GaAs peaks was discussed in terms of carrier transport and recombination properties.