Fabrication and optoelectronic properties of novel p-Si/PPy/n-CuxIn1-xO hybrid heterojunction

Abstract

In the present work, we report the photoresponse characteristics of the hybrid heterojunction consisting of polypyrrole (PPy) sandwiched between p-Si substrate and n-CuxIn1-xO film. Experimental results revealed that the PPy interlayer influence the electronic conduction through the hybrid heterojunction. Structural analysis by X-ray diffraction showed the diffraction peaks corresponding to CuO and In2O3, while the optical absorption spectra exhibited strong absorption in both the UV as well as visible regions. Morphological analysis by scanning electron microscopy showed the uniform coverage on the Si substrate, and the effective binding of CuxIn1-xO and PPy. Raman spectroscopy showed the vibration modes corresponding to CuO, In2O3 and PPy. The p-Si/PPy/n-CuxIn1-xO hybrid heterojunction demonstrated excellent rectifying behavior and improved electrical characteristics such as high rectification ratio (similar to 220), lower threshold voltage (similar to 1.8 V) and ideality factor (similar to 2.06) due to the PPy insertion and photon illumination. The enhanced electrical characteristics of the hybrid p-Si/PPy/n-CuxIn1-xO heterojunction was discussed with respect to the energy band structure, and found that the intermediate PPy layer acting as a hole transporting layer improves the charge selectivity and facilitates the effective transport of charge carriers towards the respective electrodes.