The light detection performance of the congo red dye in a Schottky type photodiode

The Congo red (CR) (3,3'-[(1,1',-biphenyl)-4,4'-diyl)bis(4-amino-1 amino naphthalene sulphonic)]) is usually used for staining of amyloidosis diseases in the diagnostic application. It shows dichroic behavior, and thus can be employed in optoelectronic applications. In this study, commercially purchased congo red dye was used as an interfacial organic layer for Schottky type photodiode to understand its sensitivity to light. The surface morphology of the CR interlayer was investigated by scanning electron microscopy (SEM), and almost uniform surface was obtained. While cobalt (Co) element was employed as metallic contact, the n -type Si and aluminum (Al) were used as a semiconductor and ohmic contact, respectively. Thus, Co/CR/n-Si device was fabricated by a spin coating and thermal evaporation technique, and characterized by I-V measurements under dark and various light power intensities. The results revealed that the congo red dye can be improved and employed for optoelectronic applications.