摘要
Plasma-enhanced chemical vapor-deposited Si O2 and Si Nx were used to passivate ZnO heterojunction light emitting diodes (LEDs). Postdielectric deposition annealing was critical in obtaining good LED electrical and optical characteristics. No diode characteristics or light emission was observed unless the structures were annealed at 350 °C after fabrication. Annealed diodes showed a band-edge electroluminescence (EL) (385 nm) and a broad defect band with a peak at 930 nm at room temperature. The Si O2 and Si Nx had very different passivation effects in terms of the electrical and EL characteristics of the LEDs. After annealing, the Si O2 passivated ZnO LEDs showed diode I-V characteristics and emitted light. However, the annealed Si Nx -passivated ZnO LEDs showed leaky diode characteristics and no light emission. We attribute these differences to the role of hydrogen on the LEDs. © 2008 American Institute of Physics.