Photoresponse characteristics of Au/(CoFe2O4-PVP)/n-Si/Au (MPS) diode

Photoresponse characteristics of the Au/(CoFe2O4-PVP)/n-Si (MPS) diode were investigated using current–voltage (I–V) measurements achieved under dark and various illumination conditions. The experimental results showed that the MPS diode has a good response to the illumination. Especially, in reverse bias region, photocurrent (Iph) increases with increasing illumination intensity (P) due to the formation of electron–hole pairs. The double-logarithmic Iph-P plot has a good relation with 1.27 slope and such high value of slope indicates a lower density of the unoccupied trap level. This indicates that the diode exhibits a good photoconductive and photovoltaic behavior. The photo-to-dark current ratio confirms the photosensitivity of the diode. Thermionic emission (TE) theory was used to determine the diode electronic parameters such as saturation current (I0), ideality factor (n) and barrier height (ΦB0) and their values were calculated from the measured I–V data. Moreover, the ΦB0 and series resistance (Rs) were extracted from an alternative method suggested by Norde. All these parameters (ΦB0, n, Rs, and I0) decrease with increasing illumination intensity and there is a good linear correlation between ΦB0 and n as ΦB0 (n) = 4.72 × 10−2n + 0.5464 eV. As a result, the fabricated MPS diode due to the excellent photoresponse can be used for photovoltaic applications.