PEI N-doped graphene quantum dots/p-type silicon Schottky diode

Abstract

Graphene Quantum Dots (GQDs) are graphene nanoparticles with exceptional properties and a remarkable material for new technologies. Especially, GQDs/semiconductor junctions (GQDs/S), which have a high potential to open doors to new fields of study such as sensing, detection, and communication have started to attract great attention in the scientific community in the last few years. Functionalization of GQDs with several functional groups to develop their properties is one of the hot topics of research. In this context, we have investigated the properties of functionalized GQDs/p-type Si diode in this study. Polyethylenimine (PEI) functionalized nitrogen-doped GQDs (PEI/N/GQDs) have been successfully produced by the hydrothermal method. Afterward, we fabricated the Al/PEI/N/GQDs/p-Si diode. The parameters of GQDs-based Schottky diode have been investigated from current-voltage (I-V) measurements at 300 K. The barrier heights (Φb) of the diode obtained from Thermionic Emission (TE) theory, Norde’s, and Cheung’s approaches are 0.76 eV, 0.82 eV, and 0.66 eV, respectively. The ratio of rectification (RR) of the diode has been calculated to be approximately 2.8 × 104 at ± 5 V. In addition, the surface state density (Nss) versus (Ess-Ev) profile of the diode has been also obtained, by taking into account the voltage dependence of the ideality factor (n) and Φb. The average value of them has been found as 1.90 × 1013 eV−1cm−2, which is very suitable for this structure. The obtained results show that the prepared Al/PEI/N/GQDs/p-Si has Schottky diode behavior.