Optimization of growth parameters of AlN thin films and investigation of electrical and electroluminescence characteristics from Au/i-AlN/n-GaN UV light-emitting diode

• The effects of substrate temperature and nitrogen to argon ratio on the physical properties of AlN films were studied. • An Au/i-AlN/n-GaN LED was fabricated, and a hole generation model and carrier transport and recombination mechanism were proposed. • The electroluminescence characteristics of Au/i-AlN/n-GaN LED at different temperatures were investigated. Aluminum nitride (AlN) film has a wide range of applications optoelectronic devices. In this paper, AlN thin films were prepared by magnetron sputtering method, the influence of substrate temperature and nitrogen-argon ratio on the structure, morphology and optical properties of AlN films were evaluated by X-ray diffractometer, scanning electron microscope and ultraviolet–visible spectrophotometer. The analysis showed that the AlN film exhibited better crystallization quality under the substrate temperature of 350 °C with a nitrogen-argon ratio of 5:40. In addition, an Au/i-AlN/n-GaN metal–insulator-semiconductor (MIS) structure device was fabricated based on high-quality AlN films. The current–voltage and electroluminescence characteristics of the device under different temperatures were studied in detail. The results showed that the device exhibited excellent rectification behavior at all operating temperatures, producing an intense UV emission (∼372 nm). This paper proposes a hole generation model and a carrier transport and recombination mechanism. The research results provide a new reference for the practical application of AlN films.