Effect of c-axis inclination angle on the properties of ZnO/Zn1 − xCdxO/ZnO quantum wells

The development of optoelectronic devices based on highly-promising Zn1 − xCdxO semiconductor system demands deep understanding of the properties of the Zn1 − xCdxO-based quantum wells (QWs). In this regard, we carried out a numerical study of the polarization-related effects in polar, semi-polar and non-polar ZnO/Zn1 − xCdxO/ZnO QWs with different parameters of the quantum well structure. The effects of well width, barrier thickness, cadmium content in the active layer and c-axis inclination angle on the distribution of the electron and hole wave function and transition energy were investigated using the 6 × 6 k·p Hamiltonian and one-dimensional self-consistent solutions of nonlinear Schrödinger-Poisson equations with consideration of spatially varying dielectric constant and effective mass. The strong sensitivity of the internal electric field, transition energy and overlap integral to cadmium content and well thickness in the angle range from 0 to 40° was revealed. An unexpected change of the internal electric field's sign was observed at the angles ranging from 70 to 90°. We also found a difference in the electronic properties between (0001)-, (112̅2)- and (101̅0)-oriented QWs.