Synthesis of graphene oxide–silver nanocomposite with photochemically grown silver nanoparticles to use as a channel material in thin film field effect transistors

Abstract

In this article we report a convenient method for synthesizing a graphene oxide (GO)–silver nanoparticle (SNP) composite and its application as a channel material in thin film field-effect transistors (TFTs). The SNPs were prepared through photochemical reduction of silver nitrate in aqueous solution using monoethanolamine (ME) as the reducing agent and sodium dodecyl sulphate (SDS) as the stabilizer. The growth of SNPs is explained with a mathematical model combining classical nucleation theory with photoinduced electron transfer theory. GO was prepared by the modified Hummer's method and SNPs were loaded to it in different concentrations for preparing the composite. The formation of composite through the ex situ process is confirmed through spectroscopic and microscopic techniques. Further, it was used as a channel layer on a SiO₂/Si substrate with a Au source and a drain for the thin film TFT in the back gated configuration. The TFT shows dominant p-type field effect characteristics compared to pure GO based TFTs. The transport of charge carriers through the channel is well tuned by controlling the dose of SNPs. The field effect mobility of the charge carriers is found to vary from 2.44 cm² V⁻¹ s⁻¹ to 1.10 cm² V⁻¹ s⁻¹ with the increase in SNP content in GO. The transport of charge carriers occurs through the channel by Fowler–Nordheim tunneling at higher gate voltages while at lower voltages multistep charge-carrier hopping occurs. Our study provides new insights in controlling transport of charge-carriers through GO to achieve tunable electrical properties for GO based electronic devices.