Electrical and photoelectrical properties of a vacuum-deposited MnClPc/n-Si heterojunction for photodiode application

Abstract

Thin films of MnClPc/n-Si heterojunctions were performed by the thermal evaporating technique. The C–V and G-V characteristics of the diode under the effect of frequency were investigated. It was found that the capacitance and the conductance spectra are significantly affected by AC-signal at the low-frequency range due to the presence of the interfacial states (Nss) and the series resistance (Rs) in the depletion region. The I–V characteristics of MnClPc/n-Si under the dark and illumination in the reverse and forward bias were studied. Under the assumption of thermionic emission theory, the rectification ratio (RR = IF/IR), the shunted and series resistances, and the ideality factor of the diode were calculated. The evaluated height potential barrier (φb) values from the I–V characteristic and by Cheung and Cheung method were 0.84 and 0.57 eV, respectively. Regarding the power-law (I ∼ Vm) relation, the charge transport mechanism is described by the space charge limited current associated with a single trap level. Moreover, the I–V characteristics under the illumination intensity were investigated. Whereas the photosensitivity readings under dark and illumination intensity reveal the probability of using MnClPc/n-Si heterojunctions as a performance photodiode sensor.