Optical and defect properties of hydrothermal ZnO with low lithium contamination

The removal of lithium and other group I contaminants from hydrothermally grown ZnO results in significant changes in its electrical, optical, and device characteristics. A significant reduction in donor compensation allows the fabrication of low series resistance Schottky contacts with extremely high rectification ratios and also quenches 4 K photoluminescence emission from excitons bound to ionized donors. Three new electron traps with activation energies of 115, 160, and 190 meV are created along with an increase in the activation energy of the dominant shallow donor from 50 to 70 eV which is associated with an accompanying removal of aluminum.