Improved white light emission from ZnS:Mn/ZnO/GaN core-shell nanorods array

By depositing ZnS:Mn films using PLD technique to coat ZnO nanorods which were grown on GaN substrate using hydrothermal method, high quality ZnS:Mn/ZnO/GaN core-shell nanorods array was prepared. The PL spectrum of ZnS:Mn/ZnO/GaN core-shell array ranges from blue-violet light to red light (400–700 nm). It consists of four luminous bands: UV light at 375 nm originating from the free exciton emission of ZnO, a blue light emission at 450 nm from GaN, an orange light emission at 590 nm mainly from ZnO nanorods and Mn²⁺ in ZnS, and a green light emission at about 530 nm related to ZnS:Mn/ZnO interface. The mechanism of green light emission is analyzed in detail. The color coordinate of ZnS:Mn/ZnO/GaN core-shell array is (0.3347, 0.318), and the color temperature is 5375 K, much closer to the standard white light when compared with other systems.