▎ 摘　　要

Despite the huge expansion of GO/rGO market, there is a clear lack of experimental studies on getting high quality, large scale GO and rGO nanosheets/thin films, which is a critical requirement for electronic applications. In this work, a detailed experimental study on the effect of lateral sheet size on properties of GO/rGO, supported by density functional theory (DFT) calculations, is presented for the first time, to help prepare pristine graphene-like rGO. Furthermore, we investigated the effect of thermal reduction at low temperature (200 SC), under ambient pressure, on the corresponding electronic properties of rGO. Current-voltage (I-V) analysis, optical and electron microscopy, atomic force microscopy, Raman, XPS, and quantitative C-13 NMR spectroscopy were used to study and optimize rGO. The optimized rGO-field-effect transistor (rGO-FET) device exhibited the highest charge carrier mobilities, i.e. 2,962 (holes) and 2,183 (electrons) cm(2)/V.s. Furthermore, the transconductance characteristic curve of rGO-FET showed the ambipolar behavior of high-quality graphene, with Dirac point around zero. In addition, the optical band gap of rGO nanosheets (similar to 0.4 eV), prepared in this work, is among the smallest reported band gaps for rGO. These findings highlight the significance of our study for synthesizing large-scale graphene-like rGO thin film, for ultra-fast, low-power transistor applications. (C) 2021 Elsevier Ltd. All rights reserved.