Investigation of CuO/Co3O4/PSi thin films for ultrafast detection of NH3 at room temperature

In this study, CuO/Co3O4/PSi thin films were fabricated and tested for NH₃ vapor detection at room temperature. The CuO/Co3O4 nanocomposite was successfully synthesized by the simple nitrate method and subsequently deposited on porous silicon (PSi) using the thermal evaporation technique. Spectral, structural, morphological, and optical characterizations were performed employing scanning electron microscopy (SEM), atomic force microscopy (AFM), fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and spectrophotometry (UV–vis). The electrical parameters of the CuO/Co3O4/PSi system, including current-voltage (I-V), sensitivity-voltage (S-V), sensivity-concentration (S-C), and current-time (I-t), were measured at room temperature in the presence of ammonia vapor. The sensor exihibited remarkable sensitivity towards NH₃ (with a response of 200 % at 170 ppm), along with short response times of 3 s and 4 s at 68 ppm and 340 ppm, respectively, and very fast recovery time of 1 s at both concentrations. Furthermore, the mechanisms for NH3 vapor sensing based on CuO/Co3O4/PSi were described. The obtained results emphasize the critical significance of the CuO/Co3O4 nanocomposite deposited on PSi in improving ammonia detection efficiency at room temperature. [Display omitted] •CuO/Co3O4 was synthesized and deposited on porous silicon (PSi) by the thermal evaporation technique.•NH3 vapor sensing based on CuO/Co3O4/PSi can be conducted at room temperature in the absence of heat or light.•Maximum response of 200 % is achieved for 170 ppm of NH3.•CuO/Co3O4/PSi demonstrated fast response and recovery times of 3 s and 1 s respectively.