Interfacial Emission Adjustment in ZnO Quantum Dots/p-GaN Heterojunction Light-Emitting Diodes

Ultraviolet (UV) light-emitting diodes (LEDs) were made by using ZnO quantum dots (QDs) as the emission layer. ZnO QDs with the diameter of 5 nm were fabricated by using a simple sintering method. By using p-GaN as the hole injection layer, a ZnO QDs/p-GaN heterojunction LED was constructed. Trap-controlled SCLC behavior of QDs led the LED to emit light mainly from the QDs layer, and the direct physical contact between ZnO QDs and GaN could effectively reduce the interfacial emission. As the result, a UV LED with the electroluminescence wavelength of 382 nm has been achieved.