Optical Properties of ZnO/MgZnO Multiple Quantum Wells Grown by Metallorganic Chemical Vapor Deposition

Abstract
We report on the optical properties of ZnO/MgZnO multiple quantum wells (MQWs) with well widths of 0.7, 1.5, and 2 nm, which were grown by metallorganic chemical vapor deposition. The temperature-dependent photoluminescence (PL) measurement showed a weak S-shaped PL property for a localized exciton emission peak with increasing the well width. The internal quantum efficiency (IQE) was increased by 75% when the well width was increased from 0.7 to 2 nm. The improved IQE and weak S-shaped PL property of MQWs with increasing the well width was attributed to decreased defect density and improved uniformity of well thickness in ZnO well layer or improved homogeneity of alloy-potentials in MgZnO barrier layers.