Photoresponse characteristics of p-Si/n-CuxIn1−xO heterojunction diode prepared by sol-gel spin coating

In the present work, we report on the fabrication and detailed electrical characterization of p-Si/n-CuxIn1−xO heterojunction prepared via the deposition of nanocrystalline CuxIn1−xO thin films on p-type silicon substrate by sol-gel method using spin coating technique. X-ray diffraction and Raman spectroscopy results revealed the polycrystalline nature of CuxIn1−xO thin films consisting diffractions peaks and vibration modes, respectively, corresponding to CuO and In2O3. Field-emission scanning electron microscopy showed compact surface morphology while UV–vis absorption spectra exhibited sharp absorption between 300 and 425 nm along with a long tail extending in the visible region. The current-voltage (I-V) characteristics of the fabricated heterojunction demonstrated obvious rectifying behavior in the dark and under illumination. The heterojunction exhibited low reverse leakage current (~10−7), and upon illumination, the forward current and rectification ratio of the junction was improved while the forward threshold voltage lowered. By fitting the experimental data we have observed that the forward current conduction is dominated by the space charge limited current mechanism.