Effects of Geometry on the Electronic Properties of Semiconductor Elliptical Quantum Rings

Abstract

ABSTRACT: The electronic states in GaAs-AlxGa1−xAs elliptically-shaped quantum rings are theoretically investigated through the numerical solution of the efective mass band equation via the fnite element method. The results are obtained for diferent sizes and geometries, including the possibility of a number of hill-shaped deformations that play the role of either connected or isolated quantum dots (hills), depending on the confguration chosen. The quantum ring transversal section is assumed to exhibit three diferent geometrical symmetries - squared, triangular and parabolic. The behavior of the allowed confned states as functions of the cross-section shape, the ring dimensions, and the number of hills-like structures are discussed in detail. The efective energy bandgap (photoluminescence peak with electron-hole correlation) is reported as well, as a function of the Al molar fraction.