A theoretical study of the effects of Thomas–Fermi and Hermanson’s dielectric functions and temperature on photoionization cross-section of a donor impurity in GaAs quantum dots of circular and rectangular cross-sections

Oketch, F.; Oyoko, H.

doi:10.1140/epjb/s10051-022-00301-4

Cited by 2 publications

(1 citation statement)

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“…We then computed the DOIS of the donor impurity as a function of the binding energies. In our calculations we have used a variational technique in the effective mass and dipole approximation [21][22][23][24]. We have assumed that Ga 1−x Al x As matrix surrounding the GaAs quantum dot (QD) provides an infinite potential barrier due to the large band gap between the two [6].…”

Section: Introductionmentioning

confidence: 99%

A theoretical study of the effects of uniaxial stress and spatial dielectric functions on the density of states of shallow donor impurities in a GaAs quantum well dot of circular geometry

Oketch,

Hannington Odhiambo Oyoko

2024

Rev. Mex. Fís.

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In the present work, we have carried out a comparative study of the effects of uniaxial stress and spatial dielectric functions on the density of impurity states (DOIS) of shallow donor impurities in a GaAs quantum well dot of circular cross-section. Using a trial wave function in the effective mass approximation, we carried out calculations for a range of binding energies of hydrogenic (dielectric constant) and non-hydrogenic (spatial dielectric functions) donors for various applied uniaxial stress and for different uniaxial lengths of the quantum dot. Our results show that, for a constant axial length of the quantum dot and constant uniaxial stress, the DOIS for the donor impurity is markedly enhanced for the non-hydrogenic donor impurity over that for purely hydrogenic donor impurity. At constant axial length, the applied uniaxial stress enhances the DOIS in both cases. The density of impurity states has also been studied for a constant applied uniaxial stress for different axial lengths of the quantum dot. Here, again, the DOIS increases with increasing axial length of the quantum dot. In fact, the enhanced DOIS is observed throughout the range of binding energies considered. These results show that not only does the DOIS vary with the applied uniaxial stress and spatial dielectric functions they are also different for various axial lengths of the quantum dot. These findings indicate that is important to take into account the effect of applied uniaxial stress and spatial dielectric functions when performing experimental studies of electronic, optical and transport properties of such nanostructures as quantum dots.

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