Microelectronic properties of VOPcPhO–\({\hbox {TiO}}_{2}\) organic/inorganic hybrid nanocomposite-based Schottky barrier diode

Abstract

This paper explores the potential application of titanium dioxide (\({\hbox {TiO}}_{2}\)) nanoparticles (NPs) to enhance the performance of Schottky barrier diode (SBD) made from vanadyl 2, 9, 16, 23-tetraphenoxy-29H, 31H-Phthalocyanine (VOPcPhO), a small-molecule organic semiconductor. The SBD is fabricated using a facile spin coating technique at ambient conditions by casting a 1:1 vol% blended suspension of VOPcPhO and \({\hbox {TiO}}_{2}\) NPs in chloroform on pre-deposited Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) on an indium tin oxide (ITO) substrate. To analyze the electronic properties of the fabricated device, current–voltage (\(I{-}V\)) measurements are performed at 25 \(^{\circ}\)C in dark conditions. The \(I{-}V\) characteristics of SBD displayed asymmetrical behavior with rectification ratio (RR) of 261 at ± 2.1 V for ITO/PEDOT:PSS/VOPcPhO–\({\hbox {TiO}}_{2}\)/Ag device which indicates the formation of a depletion region. Key electronic parameters such as charge carrier mobility (\(\mu\)), barrier height (\(\phi _{\text {b}}\)), series resistance (\({R}_{\text {s}}\)), and ideality factor (n) are derived from the \(I{-}V\) curves. Norde’s and Cheung’s methods are also used to verify the consistency of these parameters. Significant improvements in the values of \({R}_{\text {s}}\), n and RR are observed in ITO/PEDOT:PSS/VOPcPhO–\({\hbox {TiO}}_{2}\)/Ag device compared to many other Schottky barrier diodes (SBDs). This enhancement is attributed to the incorporation of \({\hbox {TiO}}_{2}\) nanoparticles which provide high surface-to-volume ratio. Additionally, the conduction mechanism in the fabricated device is analyzed by focusing on Poole–Frenkel and Richardson Schottky effects. The paper also reports Ultraviolet–Visible spectroscopy (UV–Vis) to obtain optical bandgaps (1.9 and 3.4 eV), morphology such as atomic force microscopy (AFM) and scanning electron microscopy (SEM) for high-resolution surface investigation, X-ray diffraction (XRD) for the determination of material’s crystallinity and Fourier transformed infrared (FTIR) for functional group analysis of VOPcPhO–\({\hbox {TiO}}_{2}\) nanoparticles.