Significant enhancement in photosensitivity, responsivity, detectivity and quantum efficiency of Co3O4 nanostructured thin film-based photodetectors through Mo doping developed by spray pyrolysis method

Herein, we have developed the high-performance photodetector diodes (p-Co3O4/n-Si and p-Mo@Co3O4/n-Si) by spray pyrolysis route for modern optoelectronic devices. The impact of different molybdenum (Mo) ions concentrations (0, 2, 4, and 6 wt.%) on the structural, morphological, optical and photo-electrical properties of Co3O4 films has been investigated. The X-ray diffraction study confirms the cubic phase of Mo-doped Co3O4 thin films with good crystallinity. From FESEM images, the unevenly sized sphere-like grains were clearly observed which are agglomerated at higher doping levels. UV-VIS spectra confirmed that the thin film owns good absorption and the energy gap varied with Mo doping. The p-Co3O4/n-Si and p-Mo@Co3O4/n-Si (Mo = 2, 4, and 6 wt.%) photodiodes were fabricated. The barrier height of the fabricated diodes was varied in the range of 0.65 to 0.98 eV. The maximum sensitivity of 10382% at 1.2 V has been achieved for 6 wt.% of Mo-doped diodes due to the creation of photo-created charge couples. Also, the quantum efficiency of the diode was enhanced from 39 to 164%. The 6 wt.% of p-Mo@Co3O4/n-Si junction diode exhibited the highest device performance among others and can be used as high performance photodetector.