Enhanced luminescence of quasi-double heterostructured violet light-emitting diodes based on n-Mg_0.027Zn_0.973O QD and p-Cu_1-xZn_xI thin films fabricated via simple thermal diffusion and iodination processes

The advent of GaN and its alloys has revolutionized the field of lighting. However, owing to the associated high-cost materials and vacuum-based processes, alternatives to GaN are being researched. Among recently emerging light-emitting diode (LED) materials, γ-phase cuprous iodide (γ-CuI) exhibits remarkable potential because of its wide direct bandgap (2.95 eV) and high exciton binding energy (62 meV). In this study, we fabricated violet LEDs composed of n-Mg_0.027Zn_0.973O quantum dots and p-Cu_1-xZn_xI thin films. To enhance the device performance, a quasi-double heterostructure, which is a slightly modified double heterostructure, was designed. Simple thermal diffusion of Zn and Cu iodination processes were used to realize this structure, and the LED fabricated in this manner exhibited approximately 10-fold stronger luminescence than the LED with the pristine p-CuI thin film.