Fabrication of graphene oxide/silicon nanowires heterojunction and investigation of its optical and electrical properties

Graphene oxide/silicon nanowire heterojunction was fabricated through electrochemical deposition methods. The field emission scanning electron microscopy characterization showed the graphene oxide was deposited on the silicon nanowires. The energy-dispersive X-ray spectroscopy revealed that carbon and oxygen were also present in graphene oxide/silicon nanowire heterojunction in addition to silicon. The UV–Vis IR spectra showed that at 600 nm wavelength, silicon nanowires have a reflectance value of 11% and graphene oxide/silicon nanowire has 7% ATR-FTIR and XRD characterizations further suggested the successful deposition of GO on SiNWs. The Raman spectra showed the presence of characteristic peaks of GO in addition to the peaks of SiNWs. A red shift was observed in the peaks, which may be attributed to van der Waals interactions between GO and SiNWs. The Raman analysis further confirmed the formation of GO/SiNWs heterojunction. The valance band offset and the conduction band offset of the heterojunction formed using the electrochemical method were obtained as 1.37 and 0.41 eV, respectively. The power conversion efficiency was increased from 0.18 × 10^–3 to 2.7 × 10^–3% when silicon nanowires were coated with graphene oxide. The device was stored and after 75 days, a power conversion efficiency of 88% was retained. This shows that the device is relatively stable. The present work provides a hassle-free and simple method for fabricating heterojunction at room temperature.