Molecular engineering for donor electron to enhance photodiode properties of Co/n-Si and Co/p-Si structures: The effect of hematoxylin interface

We used hemotoxylin as interlayer in between Co metal and both n-type and p-type silicon to fabricate Co/hematoxylin/n-Si and Co/hematoxylin/p-Si photodiodes. The photodiodes were characterized and compared by I-V measurements under dark and various light power intensities. The diode parameters were extracted from I-V measurements and discussed in details by thermionic emission theory, Norde and Cheung methods for dark conditions. The photodiode parameters such as photocurrent, light responsivity and detectivity were also studied and compared for two photodiodes. The obtained photodiodes exhibited good rectifying properties, but rectifying ratio (RR) values decreased with increasing light power intensity. The photodiodes exhibited linear photocurrent (Iph), good responsivity and detectivity according to results. However, the responsivity and detectivity values of the Co/hematoxylin/n-Si photodiode slightly decreased with increasing light power intensity while the Co/hematoxylin/p-Si photodiode have almost did not change. The obtained result highlighted that Co/hematoxylin/n-Si and Co/hematoxylin/p-Si photodiodes can be improved for photodiode applications.