BUILT-IN ELECTRIC FIELD EFFECT ON DONOR IMPURITIES IN STRAINED WURTZITE GaN/AlGaN ASYMMETRIC DOUBLE QUANTUM WELLS

Abstract

The ground state binding energies of donor impurities in strained [0001]-oriented wurtzite GaN / Al x Ga 1-x N asymmetric double quantum wells are investigated using a variational method combined with numerical computation. The built-in electric field due to the spontaneous and strain-induced piezoelectric polarization and the strain modification on material parameters are taken into account. The variations of binding energies versus the width of central barrier, the ratio of two well widths, and the impurity position are presented, respectively. It is found that the built-in electric field causes a mutation of binding energies with increasing the width of central barrier to some value. The results for symmetrical double quantum wells and without the built-in electric field are also discussed for comparison.

Binding energies of impurity states in strained wurtzite GaN/AlxGa1−xN heterojunctions with finitely thick potential barriers

“…The energy level E z and wave function ϕ(z) can be obtained by solving numerically Schrödinger Eq. ( 6) through using the finite difference method [38] (the obtained function is called the numerical wave function in the following) or by using a variational wave function. [39] By using the finite difference method, the eigenvalues converge to the minimum and the eigenvector and the eigenvalue can be obtained by using the iteration method until the difference between the present result and the previous result meets a certain accuracy.…”

“…To demonstrate the finite barrier effect for impurity states in a GaN/Al x Ga 1−x N heterojunction, in the paper we deal with the binding energies of impurity states using a numerical computation [38] to obtain wave functions of a bound electron in the z direction. Furthermore, it is shown that our numerical computation has a big improvement in the accuracy of the result compared with the variational method.…”

Temperature-Related Electronic Low-Lying States in Different Shapes In.1Ga.9N/GaN Double Quantum Wells under Size Effects

“…Multiple quantum wells (MQWs) based on InGaN/GaN structures with high structural and optical qualities have also been successfully fabricated and extensively investigated [25]. In addition, based on symmetric and asymmetric multiple quantum wells (MQWs) systems, several theoretical papers are reported in the literature such as double inverse parabolic quantum wells (DIPQW) [26], double symmetric and asymmetric quantum wells [27,28].…”