We report a calculation of the absorption coefficient of donor impurities located at the center of a quasi‐1D GaAs quantum well wire with finite confinement potential as a function of photon energies for different wire widths. The theory has been formulated by using suitable variational wave functions. In the presence of a uniform magnetic field applied along the axis of the wire, there is an enhancement in the absorption peak as the size of the wire is increased and a reduction of this peak as the magnetic field is increased. We see clearly that the effect of confinement is more important compared to the effect of the magnetic field. A comparison with the infinite barrier potential is also investigated.
A theoretical study of the donor-related absorption coefficient in spherical CdS quantum dots (QD) in the presence of a uniform magnetic field is performed. The wave functions and the eigenvalues of the initial and final states are obtained in the effective-mass approximation by using a variational method and a perturbation method, respectively. The results obtained show that the absorption coefficient presents essentially two peaks; one associated with on-center donors and another related to transitions involving donors at the QD edge. The dependences of the absorption coefficient on sample dimensions, the magnetic field strength and the light polarization are discussed.
The vanadium dioxide is a material thermo chromium which sees its optical properties changing at the time of the transition from the phase of semiconductor state ↔ metal, at a critical temperature of 68°C. The study of the optical properties of a thin layer of VO₂ thickness 82 nm, such as the dielectric function, the index of refraction, the coefficient ofextinction, the absorption’s coefficient, the reflectivity, the transmittivity, in the photonic spectrum of energy ω located inthe interval: 0.001242 ≤ ω (ev) ≤ 6, enables us to control well its practical utility in various applications, like the intelligentpanes, the photovoltaic, paintings for increasing energy efficiency in buildings, detectors of infra-red (I.R) or ultra-violet(U.V). We will make simulations with Maple and compare our results with those of the literature
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