Synthesis and Characterization of Reduced Graphene Oxide/Rhodamine 101 (rGO-Rh101) Nanocomposites and Their Heterojunction Performance in rGO-Rh101/p-Si Device Configuration

Reduced graphene oxide (rGO)-rhodamine 101 (Rh101) nanocomposites with different ratios of rGO have been synthesized in aqueous medium by ultrasonic homogenization. The fluorescence of Rh101 as measured using a laser dye with high fluorescence quantum yield was substantially quenched with increasing amount of rGO in the nanocomposite. Formation of rGO-Rh101 nanocomposites was confirmed by x-ray diffraction analysis, scanning electron microscopy, ultraviolet-visible (UV-Vis) spectroscopy, and fluorescence microscopy. Furthermore, rGO-Rh101 nanocomposite/p-Si heterojunctions were synthesized, all of which showed good rectifying behavior. The electrical characteristics of these devices were analyzed using current-voltage (I-V) measurements to determine the ideality factor and barrier height. The experimental results confirmed the presence of lateral inhomogeneity in the effective barrier height of the rGO-Rh101 nanocomposite/p-Si heterojunctions. In addition to I-V measurements, one device was analyzed in more detail using frequency-dependent capacitance-voltage measurements. All electrical measurements were carried out at room temperature and in the dark.