Role of Reduced Graphene Oxide-Gold Nanoparticle Composites on Au/Au-RGO/p-Si/Al Structure Depending on Sample Temperature

In order to understand the current conduction mechanism in metal-semiconductor rectifier junctions, it is important to take electrical measurements depending on the sample temperature. Therefore, the current-voltage (I-V) measurements of the Au/Au-RGO/p-Si/Al structure were taken in the temperature range of 80–300 K by steps of 20 K. In the fabrication of the Au/Au-RGO/p-Si/Al structure, p-type Si was used as a base material. First, an ohmic contact was made by evaporating Al metal on the polished surface of the chemically cleaned p-Si and annealing in a nitrogen atmosphere at 580°C. Afterwards, mercaptoundecanoic acid-capped Au nanoparticles assembled on reduced graphene oxide (RGO), namely Au-RGO nanocomposite, was grown as an interfacial layer on the p-Si semiconductor substrate by the spin coating technique. The morphological and optical properties of the Au-RGO nanocomposite thin film were examined by atomic force microscopy (AFM) and Raman spectroscopy measurements. The I-V measurements of the Au/Au-RGO/p-Si/Al structure were taken depending on sample temperature and the basic electrical parameters such as ideality factor (n), barrier height (Φ_b) and dynamic resistance were calculated by means of thermionic emission method. It was observed that the ideality factor decreased and the barrier height increased with increasing sample temperature. The results were interpreted with the barrier inhomogeneity model and using Richardson plots.