Volume 4, Issue 3, September 2018, Page: 73-77
The Effect of Hermanson’s Spatial Dielectric Function on the Density of Impurity States in a Gallium Arsenide Quantum Dot of Rectangular Cross-Section
Leonard Machuka, Department of Physics, Pwani University, Kilifi, Kenya
Hannigton Odhiambo Oyoko, Department of Physics, Pwani University, Kilifi, Kenya
Received: Aug. 19, 2018;       Accepted: Sep. 17, 2018;       Published: Oct. 17, 2018
DOI: 10.11648/j.ijamtp.20180403.12      View  1393      Downloads  119
We have carried out a theoretical study of the effect of Hermanson’s spatial dielectric function on the density of impurity states (DOIS) for a shallow hydrogenic donor impurity located in the center of a Gallium Arsenide (GaAs) Quantum Well Dot (QWD) of rectangular cross-section. The density of impurity states (DOIS) of an unscreened (hydrogenic) donor impurity was calculated and compared with that of the screened (non-hydrogenic) donor impurity for the same system. Our calculations were carried out using a trial wave function within the effective mass approximation. Our calculations have been carried out with finite barriers. In this study, we first calculated the ground state binding energies of both hydrogenic and non-hydrogenic donor impurity for different dot sizes. The donor binding energies in the two regimes are then used to compute the DOIS. The results show that for both hydrogenic and non-hydrogenic donor impurities, the DOIS sharply rises to a peak, and then decreases almost exponentially with increase in binding energy. The results also show that the DOIS obtained for the non-hydrogenic donor impurities is markedly enhanced over that for purely hydrogenic donor impurities in which a dielectric constant is employed in the potential. In fact, the enhanced DOIS is observed throughout the range of values for binding energy considered. To a good extend there is good agreement between our results and those reported in the literature. It is therefore, important that the effect of the spatial dielectric function should be considered when designing optoelectronic devices.
Density of Impurity States, Hydrogenic Donor, Non Hydrogenic Donor, Effective Mass Approximation, Spatial Dielectric Function, Quantum Dot, Donor Impurity
To cite this article
Leonard Machuka, Hannigton Odhiambo Oyoko, The Effect of Hermanson’s Spatial Dielectric Function on the Density of Impurity States in a Gallium Arsenide Quantum Dot of Rectangular Cross-Section, International Journal of Applied Mathematics and Theoretical Physics. Vol. 4, No. 3, 2018, pp. 73-77. doi: 10.11648/j.ijamtp.20180403.12
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