High performance from ZnO multiple quantum-well green light emitting diode with Li-doped CdZnO active region

A comprehensive theoretical study of Cd_0.4Zn_0.6O/ZnO multiple quantum-well (MQW) based light emitting diode (LED) is performed using a commercial TCAD simulation software. A device internal quantum efficiency (IQE) of ~94% is achieved at room temperature from such LED that, emanates at 510 nm wavelength with a turn-on voltage of 3.1 V. The effects of thickness, doping, and alloy composition of various device constituent layers are comprehensively studied while optimizing the device performance at room temperature. It is also observed that electroluminescence (EL) intensity increased by a factor of 1.25 Li doping (doping concentration=1×10¹⁸ cm^-3) of CdZnO well region, possibly due to the strain-induced piezoelectric polarization and spontaneous polarization reduction caused by Li ferroelectric dipole moment.