Achievement of a UV Photodetector Based on TiO2/CuMnO2 Heterostructures: A New Strategy

Recently, UV sensors and photodetectors have drawn growing attention due to their wide applications in environmental safety, biological research, medicine, gas sensors, optical communication, astronomical studies, space exploration, etc. Within this paper, a UV photodetector based on n-type TiO2 and p-type CuMnO2 heterojunction was successfully achieved using a simple, reproducible and cost-effective two-step method: thermal oxidation growth of TiO2 layers on titanium foil and deposition of CuMnO2 thin films by the Doctor Blade technique, respectively. To investigate the structural and morphological properties of the as-synthesized heterostructures, XRD, SEM/EDX and AFM techniques were used. Therefore, XRD analysis confirmed the phase stability and purity of the structures, while SEM and AFM revealed the uniform coverage of CuMnO2 on the polyhedral TiO2 surface. Based on Mott-Schottky results, the optoelectronic performance and the flat band potential are influenced by the thickness and roughness of the TiO2 layer. Electrical measurements demonstrated a diode-like behavior with the turn-on voltage increasing proportionally to the structure of the TiO2 layer, therefore the S2a sensor showed optimal performance with a UV sensitivity of 4.99, a response capacity of 100.6 mA mW-¹ cm², and a fast response time of 1.56 s. The results indicate that the proposed heterojunction offers a promising solution for selective and efficient UV light detection systems. In conclusion, UV photodetectors based on n-TiO2 and a p-CuMnO2 heterojunction were successfully obtained via a simple, reproducible and inexpensive method, and have great potential applications in light detection systems.