Fabrication of Cd-free ZnCuInS/ZnS based inverted quantum dot light-emitting diode: Considering substrate temperature effect on sputtered ZnO layer

Cd-free ZnCuInS/ZnS quantum dot-based light-emitting diodes (QLEDs) were fabricated using metallic sputtered ZnO. The undoped and metallic ZnO film was prepared with substrate heating to enhance the electronics properties of the oxide layer. The semiconductor properties of the ZnO layer were examined by using Hall effect measurements. The structural and morphological properties were observed using x-ray diffraction analysis and field emission scanning electron microscopy. After fabricating the QLED devices, its performances were investigated under DC electrical measurement system and compared with the preparation conditions of the ZnO films. The power efficiency of 11.6 lm/W, current efficiency of 14.1 cd/A, and external quantum efficiency (EQE) of 7.5% were achieved, where the ZnO film was prepared at the substrate temperature of 150 °C, and the Hall mobility of 23.4 cm²/Vs, carrier density of 4.1 × 10²⁰ cm⁻³ was observed accordingly.