Structural, optical, and electrical characterizations of metal-doped CuO thin films

Developing an effective photodetector with p-type semiconductor characteristics continues to play a crucial role in optoelectronic applications. This study aims to improve the performance of copper oxide (CuO) samples by different doping them with bismuth (Bi) and titanium (Ti). Bi:CuO samples with 0%, 1%, 2%, and 3% Bi were fabricated using the spin coating method. Advanced characterization techniques were employed to analyze the crystallographic, surface, and optical behaviors of the obtained thin films. X-ray diffraction (XRD) analysis revealed that the samples exhibited a polycrystalline nature with preferential growth along the (-111) and (200) orientations. The 2% Bi-doped CuO film demonstrated the most homogeneous particle-size distribution related to the other samples, while the 3% Bi-doped thin film exhibited the highest photon absorption capacity. In contrast, the 2% Bi-doped thin film provided maximum photon transmission. The direct energy band gap values of the obtained samples ranged from 1,77 eV to 1,94 eV, with the 2% Bi-doped CuO thin film exhibiting the lowest refractive index. The 2% Bi-doped CuO heterojunction photodetector showed the highest responsivity, photo-sensitivity, and photo-detectivity values while also exhibiting the shortest rise and fall times. This superior performance can be attributed to the improved crystal structure, larger crystallite size, more homogeneous particle distribution, and lower grain boundary density. These findings provide a significant pathway for the improvoment of maximum-performance and tunable photo-detectors. Undoped and 3% titanium-doped copper oxide (CuO) samples, which were gradually annealed at 480°C for approximately 1 hour using the spin coating method, were stored at room temperature on glass substrates. With titanium doping, the crystallite size increased from 21,38 nm to 30,31 nm for the (-111) oriented peak, while it increased from 24,96 nm to 25,54 nm for the (200) oriented peak. Additionally, AFM results indicated that the surface properties of the obtained thin films were not homogeneous. In conclusion, titanium doping modified the crystallite parameters of the CuO samples and improved the crystallite size. Keywords: Bi and Ti doped CuO, Thin film, XRD, Photodetector