STUDY OF AL/A-SIC/C-SI(P)/AL STRUCTURES FOR PV APPLICATION
V. Saly, J. Huran, M. Perny, M. Vary
Pages: 547-556 Published: 2 Jun 2014
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Abstract: Plasma CVD reactor was used to grow a-SiC:H on p-type crystalline silicon substrate. Identification of chemical bonds in the structure of thin amorphous layer by Fourier transform infrared spectroscopy (FTIR)and Raman spectroscopy methods was performed. DC characterization was performed in order to obtain basic electric and PV parameters of prepared sample. AC impedance spectroscopy characterization was performed in order to detect the frequency response of Al-a-SiC/c-Si(p)/Al heterojunction. The analysis of these characteristics, using the impedance spectroscopy method, has allowed the construction of the electrical equivalent circuit (EEC) of the investigated structures. EEC contains series connections of series resitance and parallel combination of thin film capacitance shunted by resistance and constant phase element (CPE) shunted by resistance. The values of the parameters of the circuit elements have been determined at room temperature in the dark and on illuminated samples in the frequency range from 1 Hz to 1 MHz and also at different forward bias voltages. The negative capacitance phenomenon was observed at lower frequencies.
Keywords: pecvd, heterojunction, silicon carbide, equivalent ac circuit, complex impedance