Si/SiO 2 Quantum Dots: Electronic Properties
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1208-O09-02
Si/SiO2 Quantum Dots: Electronic Properties I. Filikhin, S.G. Matinyan, and B. Vlahovic Department of Physics, North Carolina Central University, 1801 Fayetteville Str., Durham, NC 27707, U.S.A. ABSTRACT Spherical shaped Si quantum dots (QDs) embedded into the SiO2 substrate are considered in the single sub-band effective mass approach. The electron and heavy hole sub-bands are taken into account. The energy dependence of electron effective mass is applied especially for small size QD. Calculations of low-lying single electron and hole energy levels are performed. For QD of small sizes (diameter D ≤ 6 nm) there is a strong confinement regime when the number of energy levels is restricted to several levels. The first order of the perturbation theory is used to calculate neutral exciton recombination energy taking into account the Coulomb force between electron and heavy hole. The PL exciton data are reproduced well by our model calculations. We also compare the results with those obtained within model [1]. For weak confinement regime (size D ≥ 10 nm), when the number of confinement levels is limited by several hundred, we considered the statistical properties of the electron confinement. Distribution function for the electron levels is calculated and results are discussed. INTRODUCTION The Si/SiO2 heterostructure has wide perspectives in the application to the various optoelectronic nanodevices [2]. Theoretical study of energy spectra properties of carriers confined in the Si/SiO2 QDs is important for understanding related electronic processes. A number of works devoted to the evaluations of the electron/hole energy levels [1] have been performed under the effective mass approximation using the envelope functions. In the present work we also used this method. However our approach is supplemented by energy dependence of electron effective mass [3] which is important for small size nanocrystals (diameter D
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