Dependence of electrical parameters of co/gold-chloride/p-Si diode on frequency and illumination

Abstract

In this study, metal-semiconductor contact with an organic interlayer was fabricated. Ideality factor (n), barrier height ( φ b ), and series resistance (R s ) values for Co/Gold-chloride/p-Si structure were calculated for dark and 100–400 mW/cm 2 light illumination intensities. The current-voltage (I–V) measurements were used to extract the electrical parameters of Co/Gold-chloride/p-Si device such as ideality factor, barrier height and series resistance using different methods like thermionic emission theory and Norde method. The n values were found in the range of 2.00–2.52 and the φ b were calculated in the range of 0.50–0.53 eV and under light power intensities. Additionally, frequency-dependent capacitance-voltage (C–V) measurements were done at room temperature and frequency range from 100 kHz to 1 MHz. The results show that at sufficiently high frequencies, the interface cannot flow A.C signals. Furthermore, barrier height was also calculated from the C −2 -V plot for given the frequency range for Co/Gold-chloride/p-Si device. With this study, it has been shown that the rectifier contact of the organic-inorganic structure formed with suitable organic and inorganic semiconductor can be formed and this structure can be used in optoelectronic applications. The electrical properties of the diodes were measured with different AC signal frequencies between −2 V and +2 V in dark. During the examination of the electrical properties, it was understood that the AC signal frequency caused significant changes in the capacitance-voltage characteristic of the diode. In the capacitance-voltage graph, it was observed that a high capacitance value was obtained at low AC frequency. The increase in the frequency value caused a decrease in the capacitance value. Increasing capacitance indicates that charges are being accumulated in the measured area. Capacity increase at low frequencies indicates that charges cannot move at low frequencies, but the high frequency can move charges. Various factors play a role in the formation of these mechanisms. These can be factors such as interface states, series resistances, charges leap, etc [ 52 ]. In addition, it seems that there is no change in capacitance values at negative voltages, that is, the voltage does not affect the capacitance values in this region. A.G.Imer et al. [ 53 ] examined the frequency dependency of C–V behavior for Au/Sunset Yellow/n-Si Schottky architecture and they found that the capacitance value increases with the frequency in the forward bias regime for the fabricated photodiode. A. Kocyigit et al. [ 54 ] carried out C–V characterizations of Al/AB/p-Si devices and they revealed that the electrical properties of those devices are a powerful function of voltage and frequency. • Gold-chloride thin films were deposited on the p-Si substrate by sol-gel spin coating method. • Co/Gold-chloride/p-Si structure was fabricated. • Photoconductivity properties of the photodiode were investigated by current-voltage measurements. • Electrical properties were analyzed by frequency-dependent capacitance-voltage measurements.