2025/12/08 by Tran, Bao Quan, Ngo, Nhu Huynh, Nguyen, K.B. +5
Engineering · Materials Science · #Thin-Film Transistor Technologies #Transition Metal Oxide Nanomaterials #ZnO doping and properties
paper · doi:10.18149/mpm.5342025_10
openalex publication_date 2025/12/08 · openalex created_date 2025/12/10 · openalex updated_date 2026/07/01
This study focuses on the fabrication and investigation of the properties of the heterojunction p-NiO/n-Al- doped ZnO via the radio frequency magnetron sputtering method. We conducted a detailed evaluation of the crystal structure, optical properties, and electrical properties of the NiO and Al-doped ZnO monolayers using advanced techniques such as X-ray diffraction, ultraviolet-visible spectroscopy, and Hall effect measurements. X-ray diffraction results show that the NiO thin film crystallizes in the (111) and (200) peaks with a characteristic NaCl-type cubic structure, while the Al-doped ZnO thin film preferentially develops in the (002) peak, exhibiting a hexagonal wurtzite structure. UV–Vis transmission spectrum analysis indicates that the NiO and Al-doped ZnO thin films exhibit transmittance rates of 52 and 92 % in the visible light region, respectively. The optical band gap energy was determined to be 3.45 eV for NiO and 3.36 eV for Al-doped ZnO, respectively. In addition, the carrier concentration in both single layers reached a high level, around 1019 cm-3. The J-V characteristics under optimal conditions confirmed the formation of the NiO/AZO heterojunction with a turn-on voltage of 0.67 V, an ideality factor of 4.44, and a barrier potential height of 0.5 eV. Especially, the influence of light with a wavelength of 365 nm, this heterojunction clearly exhibited the characteristics of a photodiode. These results demonstrate the remarkable potential applications of the p-NiO/n-AZO heterojunction in the fields of optoelectronics and light sensors.