A new approach to white light emitting diodes of p-GaN/i-ZnO/n-ZnO heterojunctions

A simple method to fabricate one-chip white light emitting diodes (LEDs) is proposed. A series of p-GaN/i-ZnO/n-ZnO heterojunctions fabricated by pulsed laser deposition exhibit simultaneous Mg-related p-GaN (blue-violet) and deep-level i-ZnO (yellow) emissions under forward bias. Current-voltage measurements show a typical rectifying characteristic. Yellow emission intensity, and consequently the ratio of yellow to blue-violet emission, are tunable through control of the i-ZnO layer thickness. Heterojunctions with a 20 nm-thick i-ZnO layer exhibit white electroluminescence.