Exciton properties in zincblende InGaN-GaN quantum wells under the effects of intense laser fields

ABSTRACT: In this work, we study the exciton states in a zincblende InGaN/GaN quantum well using a variational technique. The system is considered under the action of intense laser fields with the incorporation of a direct current electric field as an additional external probe. The effects of these external influences as well as of the changes in the geometry of the heterostructure on the exciton binding energy are discussed in detail

Hydrostatic pressure and electric field effects on the normalized binding energy in asymmetrical quantum wells

We have investigated the simultaneous effects of the hydrostatic pressure and electric field on the ground subband level and on normalized binding energy of an on-center donor in asymmetrical GaAs/AlGaAs quantum wells within the effective-mass approximation and a variational approach. We found that the well size at which the impurity energy changes from positive to negative value (turning point) strongly depends on the asymmetry and hydrostatic pressure. As a key result, we suggest that the study of the normalized binding energy for various values of the electric field in direct and inverse polarization regimes can be used to feel the quantum well asymmetry and to unambiguously find out the effective pressure acting on a given heterostructure

Interband absorption in square and semiparabolic near-surface quantum wells under intense laser field

The exciton effects on the interband absorption spectra in near-surface square and semiparabolic quantum wells under intense laser field are studied taking into account the correct dressing effect for the confinement potential and electrostatic self-energy due to the repulsive interaction between carriers and their image charges. We found that for near-surface quantum wells with different shapes the laser field induces significant effects on their electronic and optical properties. The numerical results for the InGaAs/GaAs system show that the red-shift of the absorption peak induced by the increasing cap layer can be effectively compensated using the blue-shift caused by the enhanced laser parameter. In square quantum well without laser field our theoretical values for the absorption peak position are in good agreement with the available experimental data. As a key result, we conclude that the optical properties in near-surface quantum wells can be tuned by tailoring the heterostructure parameters: well shape, capped layer thickness and/or dielectric mismatch as well as the external field radiation strength