Enhanced ultraviolet emission of MgZnO/ZnO multiple quantum wells light-emitting diode by p-type MgZnO electron blocking layer.

We report on the effect of a p-type MgZnO electron blocking layer (EBL) on the optical and electrical properties of MgZnO/ZnO multiple quantum wells (MQWs) light-emitting diodes (LEDs). The p-type Mg(0.15)Zn(0.85)O EBL was introduced between the MQWs and p-type Mg(0.1)Zn(0.9)O layers. The p-type Mg(0.15)Zn(0.85)O EBL increased the ultraviolet emission by 111.2% at 60 mA and decreased the broad deep-level emission from ZnO LEDs. The calculated band structures and carrier distribution in ZnO LEDs show that p-type Mg(0.15)Zn(0.85)O EBL effectively suppresses the electron overflow from MQWs to p-type Mg(0.1)Zn(0.9)O and increases the hole concentration in the MQWs.