Comparison of n and p type Si-based Schottky photodiode with interlayered Congo red dye

Abstract

We synthesized a thin film of Au nanoparticles-decorated Congo red (CR) dye on both n-Si and p-Si substrates by the spin coating technique. UV-Vis spectrometer was used to determine the absorbance and band gap of the CR film. Transmission electron microscope (TEM) was used to assess the distribution of Au nanoparticles on the CR dye film. Then, the metal-semiconductor devices were fabricated by evaporation of Co metal and Al ohmic contacts on the front and back surfaces of the CR film-covered substrates, respectively. Thus, Co/CR:Au/n-Si and Co/CR:Au/p-Si Schottky photodiodes were fabricated and characterized by I-V measurements under dark and various light power illumination intensities at room temperature. The devices exhibited good rectifying behaviors and low barrier heights. Various diode parameters such as ideality factor, barrier height, and series resistance values were calculated and compared for the two fabricated photodiodes. The Co/CR:Au/n-Si and Co/ CR:Au/p-Si devices exhibited good photodiode and photodetector properties. Various detection parameters revealed that the obtained devices can be improved for optoelectronic applications.