STRUCTURAL CHARACTERIZATION OF ZnSe/GaAs INTERFACE BY X-RAY REFLECTION

A.Ulyanenkov¹, K.Ishida², M.Kuribayashi², A.Takase²

¹ Institute of Nuclear Problems, Bobruiskaya Str.11, 220050 Minsk, Republic of Belarus
² Science University of Tokyo, Yamazaki 2641, Noda-shi, Chiba 278, Japan

ZnSe/GaAs heterostructure has been investigated by x-ray reflectivity method. The analysis of structure and morphology of interface between ZnSe film and GaAs substrate was emphasised. The experimental curves at different wavelengths from two samples, grown by molecular beam epitaxy (MBE), were simulated by means of distorted-wave Born approximation method [1]. Two samples differed in initial growing conditions, the first was prepared by Se-treatment of GaAs substrate, and the second one was exposed by Zn before ZnSe film growth. The fitting of experiments indicated the presence of Ga₂Se₃ intermediate layer between ZnSe film and GaAs buffer layer both for Se- and Zn-treated samples. The extracted from best fits values of Ga₂Se₃ concentration at interface, both being non-equal to unity, allows to assume the discontinuity of interlayer, i.e. the island-like morphology of latter [2]. The preference of Zn-treatment during the MBE process is confirmed [3] by comparing the fitted densities of Ga₂Se₃ for both growing modes.

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