Electrical and Photoconductivity Properties of Al/CdFe 2 O 4 /p-Si/Al Photodiode

Abstract

In the present study, we have investigated the effects of illumination intensity on the optical and electrical characteristics of the Al/CdFe 2 O 4 /p-Si/Al photodiode. A thin film of CdFe 2 O 4 was fabricated using the sol-gel spin coating method that allows good thickness control and low-cost manufacturing as compared to alternative techniques. The current-voltage ( I-V ) of the Al/CdFe 2 O 4 /p-Si/Al photodiode was measured in the dark and under different illumination intensities. The photocurrent increased with higher luminous intensity and its sensitivity has a strong dependence on the reverse bias rising from 1.08 ⁎ 10 - 7 A under dark conditions to 6.11 ⁎ 10 - 4 A at 100 mW/cm 2 of illumination. The parameters of the photodiode such as ideality factor and barrier height were calculated using the thermionic emission model. The ideality factor of the Al/CdFe 2 O 4 /p-Si/Al photodiode was found to be 4.4. The barrier height was found to be 0.88 eV. The capacitance-voltage ( C-V ) characteristics measured at different frequencies have strongly varied with frequency, decreasing with frequency. Consequently, the resulting interface density ( D i t ) value of the Al/CdFe 2 O 4 /p-Si/Al photodiode also decreased with higher frequency. Similarly, the fitted series resistance of the Al/CdFe 2 O 4 /p-Si/Al photodiode has declined with higher frequency.