Fabrication of Illumination-Dependent Cu/p-Si Schottky Barrier Diodes by Sandwiching MoO3 Nanoplates as an Interfacial Layer via JNSP Technique

Highly oriented ultrathin MoO3 nanoplate thin films have been synthesized on a large scale using a low-cost spray pyrolysis technique at different substrate temperatures (350°C, 400°C, 450°C, and 500°C). High-quality single-phase orthorhombic α-MoO3 nanoplate film was observed by x-ray diffraction analysis. The surface morphology of the coated films was analyzed by field-emission scanning electron microscopy, revealing two different surface structures, viz. nanorods and nanoplates. Under atomic force microscopy, the surface roughness of the films was found to decrease with increasing substrate temperature. The optical properties of the α-MoO3 nanoplate thin films were analyzed by ultraviolet–visible and photoluminescence spectroscopy. The optical bandgap varied from 2.8 eV to 3.2 eV, recording a red-shift in the emission, with increasing substrate temperature from 350°C to 500°C. The electrical conductivity was also found to increase linearly with increasing substrate temperature. Various photodiode parameters such as ideality factor (n), barrier hight (ФB), photo sensitivity (PS), resistivity (R), quantum efficiency (QE) and detectivity (D*) were calculated for different light intensities from 0 mW/cm2 to 120 mW/cm2 based on the I–V characteristic. The diode fabricated at 500°C showed a remarkably high photosensitivity and specific detectivity of 610.51% and 1.149 × 1011 Jones when measured at 120 mW/cm2.