Enhancement in the Microelectronic Properties of PANI/n-Si Heterojunction by Employing ZnO Nanoparticles

This paper explores the significance of inorganic semiconductor zinc oxide (ZnO) nanoparticles (NPs) in enhancing the microelectronic of a semiconducting polymer polyaniline (PANI) for its applications in heterojunction devices. The hybrid PANI-ZnO nanocomposite (NC) possesses both characteristics of the conducting polymer PANI as well as the inorganic ZnO NPs. The Ag/PANI-ZnO/TiO 2 /n-Si heterojunction device is fabricated via simple spin coating technique by depositing a thin layer of PANI-ZnO NC on pre-deposited TiO 2 layer/n-silicon (n-Si) substrate. TiO 2 acts as buffer layer between n-Si and PANI-ZnO NC films to facilitate electron transport at the interface. To study microelectronic properties of the fabricated Ag/PANI-ZnO/TiO 2 /n-Si heterojunction, current-voltage ( I–V ) characteristics are carried out at 300 K in dark conditions (0 lux). The dark I–V curves of the device show asymmetric behavior with a rectification ratio (RR) of 193 at ±2.5 V that testifies the formation of heterojunction device. The governing interface parameters of the device such as series resistance (R s ), shunt resistance (R sh ), ideality factor (n), charge carrier mobility ( μ ) and barrier height ( ϕ b ) are measured by conventional I-V method to investigate the interface properties of the heterojunction based on PANI-ZnO NC. Results obtained show that the application of ZnO NPs enhances the microelectronic characteristics of the device as compared to stand-alone polymer devices. The measured device parameters are verified by the Cheungs’ functions and charge carriers’ conduction mechanism is probed by Mott-Gurney model. Structural, optical bandgap and morphological features of PANI-ZnO NC are investigated by X-ray diffraction (XRD), ultraviolet-visible (UV–vis) spectroscopy and scanning electron microscopy (SEM) as well as atomic force microscopy (AFM).