Design and simulation of ZnO-based light-emitting diode structures

Abstract

Two different types of ZnO-based light-emitting diode structures have been examined using a one-dimensional (1D) simulator that accounts for specific features of the hexagonal semiconductors—strong piezoeffects, existence of spontaneous electric polarization, low efficiency of acceptor activation, and high threading dislocation density (normally, ∼107–109cm−2) in the material. A hybrid ZnO∕CdZnO∕AlGaN∕GaN structure grown on sapphire avoids problems in achieving robust p-type doping in ZnO. An all-ZnO approach employs a MgZnO∕CdZnO∕MgZnO double heterostructure grown on a ZnO substrate. Both structures show a strong sensitivity of emission intensity to doping and layer thicknesses within our simulations.