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Despite much attention on the photoelectronic device applications of CuO-based materials, a thorough analysis of optical properties and electronic band structure of Ni-doped CuO films is still nece...

P-type CuO films were prepared by solution processed method and annealed at 300 °C with the annealing time of 10, 30, 60, 90, and 120 min, respectively. X-ray diffraction and atomic force microscopy results reveal that the CuO film microstructures, crystallinity and grain size can be modified by annealing time. The CuO film annealed at 30 min exhibits the optimal crystalline quality. The annealing time shows a significant impact on the mobility, Ion/Ioff ratio and subthreshold swing (SS) values of the prepared CuO thin-film transistors (TFTs). By changing the annealing time, the mobility increases from 1.6 × 10−4 to 1.2 × 10−2 cm2 V−1 s−1 while the Ion/Ioff ratio increases from 2 × 103 to 2 × 104. Moreover, the transistor with annealing time of 30 min achieves the optimal field-effect mobility (1.2 × 10−2 cm2 V−1 s−1), Ion/Ioff ratio (2 × 104), and SS value (6.3 Vdec−1). It can be ascribed to fewer grain boundaries and better interface contact of the CuO film, which will reduce the densities of trapping centers and scattering centers. This work demonstrates that the crystalline quality and microstructures of CuO film and TFTs performance can be modulated by annealing time.

Photodetectors based on p-type metal oxides are still a challenge for optoelectronic device applications. Many effects have been paid to improve their performance and expand their detection range. Here, high-quality Cu1-xNixO (x = 0, 0.2, and 0.4) film photodetectors were prepared by a solution process. The crystal quality, morphology, and grain size of Cu1-xNixO films can be modulated by Ni doping. Among the photodetectors, the Cu0.8Ni0.2O photodetector shows the maximum photocurrent value (6 × 10-7 A) under a 635 nm laser illumination. High responsivity (26.46 A/W) and external quantum efficiency (5176%) are also achieved for the Cu0.8Ni0.2O photodetector. This is because the Cu0.8Ni0.2O photosensitive layer exhibits high photoconductivity, low surface states, and high crystallization after 20% Ni doping. Compared to the other photodetectors, the Cu0.8Ni0.2O photodetector exhibits the optimal response in the near-infrared region, owing to the high absorption coefficient. These findings provide a route to fabricate high-performance and wide-detection range p-type metal oxide photodetectors.