Doping of graphene oxide structure with silver atoms at cryogenic temperature and investigation of its plasmonic properties

In this thesis, graphene oxide (GO) structure was doped with silver (Ag)atoms at cryogenic temperature (200 K) for the first time and the obtained binary structure (GO/Ag) was given plasmonic properties. In this direction, graphene oxide (GO) production was carried out from Sigma-Aldrich brand graphite powder using the Modified Hummers method. X-ray diffraction diffractometer (XRD) and scanning electron microscope (SEM) analyses were performed to determine the GO structure in the produced sample. The analysis results showed that the produced samples had a GO structure. Then, GO powder was made into tablets with the help of a press machine and the surfaces of the tablets were coated with Ag using the cold substrate method. Optical measurements of the obtained Ag-doped (GO/Ag) and undoped (GO) structures were made and forbidden energy band gaps (Eg) were calculated. It was determined by optical measurements that the surface plasmon resonance (SPR) event occurred at a wavelength of 450 nm in the Ag-doped and undoped samples. In XRD patterns, reflection peaks belonging to silver oxide (Ag2O, Ag2O3) and metallic silver (Ag) atoms were observed in the GO/Ag binary structure. SEM images showed that the number of layers of the GO/Ag structure was higher than that of GO. From FT-IR analyses, it was determined that there were various bond vibrations (3222, 1719, 1619, 1407, 1155, 1035, 874 cm-1) belonging to the GO structure (carbon, oxygen, hydrogen). Moreover, in Raman analyses, it was calculated from the ID/IG values that the defect density in the GO/Ag structure decreased. Nyquist curves of the samples illuminated at different wavelengths (room,366 nm and 450 nm) were obtained by electrochemical impedance spectroscopy (EIS) method and their charge transfer resistances were calculated. EIS results showed that the charge transfer resistance of GO/Ag changed depending on the wavelength. In the second stage of the study, Al/p-Si/GO/In and Al/p-Si/GO+Ag/In diodes were created. The current-voltage (I-V) characteristics of the diodes were examined in dark and bright (93 mW/cm2) environments. The results obtained showed that the silver-doped Al/p-Si/GO+Ag/In diode exhibited better electrical properties. As a result of this thesis study, it was seen that the plasmonic GO/Ag structures obtained with the new method were suitable for use in electronic device production.