A Novel Electrochemical Exfoliation Route to Tailor Graphene Bandgap through Silicon Incorporation: Semi-metallic to Semiconducting Transition

Abstract

Graphene-silicon (Gr-Si) composites were produced by powder compaction followed by low-temperature sintering and subsequent electrochemical exfoliation, which was then improved by electrochemical exfoliation to provide materials with variable band gaps for semiconductor applications. To create two-dimensional composites, graphite and silicon powders were mixed in various ratios (85:15, 80:20, and 75:25), compressed into tablets, and then exfoliated. XRD, Raman spectroscopy, FTIR, UV-Vis spectroscopy, FESEM/ EDX, TGA, DSC, and conductivity measurements were used to methodically describe the structural, morphological, thermal, optical, and electrical characteristics. With increased silicon content widens the bandgap widens due to stronger Si-O-C networks/localization, the results showed clear bandgap tunability between 1.25 eV and 1.56 eV, along with changes in conductivity, defect density, and crystallinity. While graphene-rich composites showed better conductivity, Si-rich composites showed enhanced thermal stability and a larger bandgap. The potential applications of Gr-Si composites in transistors, photodetectors, solar cells, and other cutting-edge semiconductor devices are highlighted by the synergistic synthesis of silicon's semiconducting properties with graphene's carrier mobility.