Piezoreflectance and photoreflectance study of annealing effects on GaAs0.916Sb0.084 and GaAs0.906Sb0.075N0.019 films on GaAs grown by gas-source molecular beam epitaxy

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Abstract

Thermal annealing effects of GaAs0.916Sb0.084 and GaAs0.906Sb0.075N0.019 films grown on GaAs substrates by gas-source molecular beam epitaxy have been characterized by piezoreflectance (PzR) and photoreflectance (PR). By a comparison of relative intensity of PzR and PR spectra, the identification of conduction to heavy-hole (HH) band and conduction to light-hole (LH) band transitions originated from the strained induced valence band splitting have been achieved. The near band edge transition energies are blue-shifted, and the splitting of HH and LH bands is reduced after thermal annealing treatment. The annealing effects of GaAs0.906Sb0.075N0.019 are found to be more pronounced than that of GaAs0.916Sb0.084. The temperature dependences of near band edge transition energies are analyzed using Varshni and Bose–Einstein expressions in the temperature range from 15 K to 300 K. The parameters that describe the temperature variations of the near band edge transition energies are evaluated and discussed. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

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