Improving light-sensing behavior of Cu/n-Si photodiode with Human Serum Albumin: Microelectronic and dielectric characterization

This research was mainly focused on the investigation of the effect of Human Serum Albumin (HSA) on the electrical features of Cu/n-Si device. To do this, HSA layer was grown as an interfacial layer between Cu and n-Si to create Cu/HSA/n-Si device. To investigate the performance of the obtained device architecture in optoelectronic applications, the electrical and photoresponse properties of the device were evaluated by current-voltage measurements at different light power intensities. The results show that as well as the device showed a good rectification characteristic in the dark, it also showed that it exhibits a good photodiode property at different light intensities. Besides, main diode parameters such as ideality factor, effective barrier height, and series resistance were evaluated by thermionic emission theory and Cheung approximation. Obtained results from both calculation methods revealed that diode parameters highly depend on the light power intensity. This variation in the diode parameter is explained in detail taking electron-hole formation in the HSA and n-Si into consideration. Besides, the capacitive properties of the device were investigated with capacitance-voltage measurements in the frequency range of 200 and 1000 kHz and it was observed that the device exhibits capacitive properties in this range. Furthermore, main dielectric parameters such as dielectric constant, dielectric loss, and loss tangent were also evaluated by using impedance spectroscopy in the different frequency range and results showed that all-dielectric parameters highly depend on frequency. All obtained results have been discussed in detail.