Electronic band structure of GaAs/AlxGa1−xAs superlattice in an intense laser field

ABSTRACT: We perform theoretical calculations for the band structure of semiconductor superlattice under intense high-frequency laser field. In the frame of the non-perturbative approach, the laser effects are included via laser-dressed potential. Results reveal that an intense laser field creates an additional geometric confinement on the electronic states. Numerical results show that when tuning the strength of the laser field significant changes come in the electronic energy levels and density of states

The effect of magnetic field on the impurity binding energy of shallow donor impurities in a Ga1−xInxNyAs1−y/GaAs quantum well

ABSTRACT: Using a variational approach, we have investigated the effects of the magnetic field, the impurity position, and the nitrogen and indium concentrations on impurity binding energy in a Ga1−xInxNyAs1−y/GaAs quantum well. Our calculations have revealed the dependence of impurity binding on the applied magnetic field, the impurity position, and the nitrogen and indium concentrations

Effects of applied electric and magnetic fields on the nonlinear optical rectification and second-harmonic generation in a graded quantum well under intense laser field

In this present study, the effects of electric and magnetic fields on the nonlinear optical rectification and second-harmonic generation in a graded quantum well under intense laser field have been investigated theoretically. The energy eigenvalues and their corresponding eigenfunctions are obtained by solving Schrödinger equation within the framework of effective mass approximation. The analytic expressions for the optical properties are calculated by the compact-density-matrix approach and iterative method. The numerical results are presented for a typical GaAs/Ga1−xAlxAs quantum well. The results show that the nonlinear optical rectification and second-harmonic generation coefficients are considerably affected by the electromagnetic fields and intense laser field

The variation of electronic properties with the doping concentration of modulation-doped AlxGa1-xAs-GaAs double quantum wells

In this paper we have calculated the sub-band structure and the confinement potential of modulation-doped Ga1-xAlxAs-GaAs double quantum wells as a function of the doping concentration. The electronic properties of this structure were determined by self-consistent solutions of the Schrodinger and Poisson equations. To understand the effects of doping concentration on band bending, sub-band energies, and sub-band populations, the doping concentration on one right side of the structure is decreased while holding it constant on the left side. We found that at low doping concentrations on the right side, the effects of the doping concentration are more pronounced on band bending and sub-band populations. (c) 2006 Elsevier Ltd. All rights reserved

Photoluminescence characteristic of as-grown and thermally annealed n-and p-type modulation-doped Ga(0.68)In(0.32)N(x)AS(1-x)/GaAs quantum well structures

The electronic band structure of n- and p-type modulation-doped Ga0.68In0.32NyAs1-y/GaAs (y=0, 0.9, 1.2, 1.7) quantum well is calculated using the 10 band k.p model and the finite element method for valance band (VB) and band anti-crossing model for conduction band. Experimental characterization has been carried out temperature dependent photoluminescence (PL) measurements at room temperature. It is determined that optical transition occurs between the first quantized energy level in the conduction band (CB) and VB for n-type samples. While it occurs between localized level and VB, due to empty of the localized level closes CB for p-type samples. It is observed that the intensity of PL emission is higher for p-type samples and the effective bandgap energy redshifts with increasing Nitrogen (N) concentration. Rapid thermal annealing improves the optical quality and causes a blueshift effect. We have determined a similar amount of the blueshift for n-type N-free and N-containing samples, which may be the interdiffusion of the In/Ga atoms. The temperature dependency of the bandgap energies has been fitted using a semi-empirical Varshni equation. It has been observed that thermal Debye temperature and thermal expansion coefficient decreases with N. The redshift of the temperature dependence of the bandgap becomes larger as N concentration decreases. On the other hand, the annealing process causes a reduction in the temperature dependency of the bandgap for p-type sample