Nitrogen doping of ZnTe for the preparation of ZnTe/ZnO light-emitting diode

Nitrogen-doped p -type zinc telluride ( p -ZnTe) films are prepared by sputtering in a mixture of nitrogen/argon plasma. The effect of doping level N (ratio of N 2 flow rate to that for the mixed gas) in the range 0–10 % on the films properties is investigated. Heterojunction diodes are prepared on stainless steel flexible substrate from the p -ZnTe (doping level, N = 5 %) and solution-grown n -ZnO films. The junction parameters and light-emission properties of diodes are investigated. Doping level beyond N = 1 %, changes the cubic crystal structure of ZnTe to hexagonal and reduces the size of crystallites. At the doping level N = 2–4 %, films with the highest hole density of 2.5 × 10 18 cm −3 and lowest band gap energy of 1.4 eV are obtained. The diodes junction built-in potential and the donor density in n -ZnO films are found to be in the range 0.4–0.7 V and 1.5 × 10 17 –1.4 × 10 18 cm −3 , respectively. Diodes exhibit electroluminescence in the UV and visible regions due to the band edge and defect emissions in ZnO.