Dominant ultraviolet light emissions in packed ZnO columnarhomojunction diodes

The growth of Sb-doped p -type Zn O ∕ Ga -doped n -type ZnO homojunction on Si (100) substrate by molecular beam epitaxy led to closely packed vertical ZnO columns with lateral diameters ranging from 100 to 400 nm . Mesa structures were defined and Ohmic contact of both n -type ZnO and p -type ZnO was realized with Au ∕ Ti and Au ∕ Ni O , respectively. I - V and C - V curves present typical electrical properties of a diode, indicating that reliable p -type ZnO was formed. Electroluminescence shows dominant ultraviolet emissions with insignificant deep-level related yellow/green band emissions at different drive currents from 60 to 100 mA at room temperature.