Novel core-shell heterostructures: investigation of high-efficiency uv light detection mechanism of Ag@CuxO and Ag@CuxO:rGO devices

In this thesis, colloidal Ag@CuxO and Ag@CuxO:rGO core@shell nanocomposite structures were synthesized by wet chemical methods and analyzed by UV-Vis, XRD, XPS, SEM, and TEM. The colloidal structures were deposited onto n-Si wafers using the drop casting method to synthesize n-Si/Ag@CuxO and n-Si/Ag@CuxO:rGO heterojunction devices. Current-voltage measurements of these devices were performed at different light intensities and wavelengths of 365, 395, 590, and 850 nm. The ideality factor, barrier height, and series resistance values of Schottky diodes were calculated using Thermionic Emission Theory and Cheung and Norde methods. The capacitance-voltage characteristics of the photodiodes were investigated, and it was observed that the devices could not transmit AC signals at high frequencies and therefore exhibited low capacitive properties. In the photodetector performance analysis, the responsivities for both devices were found to be 1.53 A/W and 4.26 A/W (365 nm, -2 V), respectively, and the external quantum efficiency exceeded 100%. The higher performance of the n-Si/Ag@CuxO:rGO device under UV light compared to the n-Si/Ag@CuxO device was attributed to the high electron mobility of rGO, and it was observed that the nanocomposite structures offer excellent photodetector performance under UV light. These findings indicate that these structures have great potential for advanced optoelectronic applications.