The light absorption of a ZnS quantum dot with a parabolic confinement potential is studied in this paper in the presence of magnetic field perpendicular to dot plane. The Schrodinger equation of a single electron is solved numerically, and energy spectra and wave functions are obtained. Then, the optical absorption coefficients in transition from ground state to different excited states are calculated. The effects the magnetic field and quantum dot width on the optical absorption are investigated. It is found that the optical absorption coefficient has a blue shift by increasing of magnetic field or confinement strength of quantum dot. 1. Introduction During the last ten years, with great progress in nanofabrication techniques, it is possible to grow semiconductor quantum dots (QDs) with various shapes and sizes [1]. QDs are semiconductor nanocrystals that can be considered as artificial atoms because they have discrete energy levels and shell structure [2]. The main advantage of QD relative to real atom is that the physical properties of QDs can be controlled by tuning their size and shapes. The QDs have various applications; in particular in the mid- and far-infrared regions, they can be used for pollution detection, thermal imaging object location, and remote sensing as well as infrared imaging of astronomical objects [3]. This nanostructure can be formed by modern growth methods such as molecular beam epitaxy [4] and the Stranski-Krastanov growth method [5, 6]. Recently, the synthetic chrysotile nanotubes have been synthesized by Roveri et al. [7]. These geoinspired nanotubes can be prepared with specific properties, finalized to focused achievements such as preparation of new quantum wires. On the other hand, an experimental study is carried out on assembling ZnS QDs in synthetic chrysotile nanotubes [8]. These assembling QDs affect significantly the optical properties of the synthetic chrysotile nanotube. Due to potential application of these nanotubes as nonlinear optical and conducting technological devices, investigation of the electronic and optical properties of these systems is essential. In this paper, we investigate the light absorption in a ZnS QD. The effects of magnetic field and geometrical size of ZnS QD on the light absorption are investigated theoretically. Thus far, the optical properties of QDs are studied by some authors [9–13]. The first study of optical absorption in QD has been carried out theoretically by Efros and his colleague [9]. They have investigated the peculiarities of interband optical absorption in spherical QD. In
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