Fabrication of New Mid-Infrared Photodetectors Based on Graphene Modified by Organic Molecules

In this paper, for the first time, graphene nanoparticles modified by organic molecules (thiophene-2-carbaldehyde, thiophene-2-carboxylic acid, or pyridine-4-carboxylic) are used for the fabrication of infrared (IR) detectors. To compare the results, the properties of the photodetector fabricated based on the synthesized unmodified graphene were also investigated. The proposed IR detectors are fabricated through coating the synthesized graphene nanoparticles on interdigitated Cu electrodes. The results indicate that the modified graphene-based detectors exhibit high electrical stability compared with the unmodified graphene. Moreover, the detector based on pyridine-4-carboxylic acid-graphene shows excellent characteristics with low dark current and sensitive and fast detection. The temporal response for this detector is 38 ms rise time with responsivity of 2.5 A/W and sensitivity of 1.5.