Donor-related magneto-optical absorption spectra of GaAs - (Ga, Al)As quantum wells

Abstract

The effects of applied magnetic fields on the optical absorption spectra associated with transitions from the Landau valence magnetic levels to shallow donor states in GaAs - (Ga, Al)As quantum wells are studied for magnetic fields applied perpendicular to the heterostructure interfaces. The donor-related magneto-absorption spectra are calculated within the effective-mass approximation, and with a minimization procedure for evaluating donor energies and envelope wave functions. We consider a homogeneous donor distribution in the well and analyse the theoretical impurity-related magneto-absorption spectra for various quantum well widths and applied magnetic fields. The magneto-absorption lineshapes present features clearly associated with transitions involving donor states and different valence Landau magnetic levels.

Impurity-related optical-absorption spectra inGaAs−Ga1−x<

“…We observe that there is a noticeable peak structure associated with impurities located at the center of the wells. It is important to mention that recently, Barbosa et al 11 have found for the impurity-related optical absorption spectra in GaAs OW's with a magnetic field applied in the growth direction, two structures associated with impurities at the center and at the border of the heterostructure. Similar results were found for quantum wells, 7-9 quantum-well wires, 23 and quantum dots 21 without applied magnetic fields.…”

Magnetic field effect on the binding energy of a hydrogenic impurity in GaAs-Ga1−xAlxAs superlattice

“…with α being a variational parameter obtained by minimizing the impurity energy [24][25][26] and A constant being the normalization factor. The binding energy of the impurity is given by…”