Graphene-based transparent and tunable plus-shaped refractive index sensor for detecting waterborne bacteria

Waterborne bacteria cause many dangerous diseases as well as several health-related issues hence detection of them is a global challenge today. A plus-shaped graphene sensor to detect waterborne bacteria is presented in this paper. The detection mechanism is based upon the refractive index difference between waterborne bacteria sample and pure water which causes a change in resonance peak in the transmittance graph. The use of graphene material increases the sensitivity and also gives the tuning behavior by changing its potential. The effect of various parameters such as sensitivity (S), Q factor, figure of merit (FOM), and detection limit are discussed in the paper. The maximum values Q factor and FOM are 13.46 and 4.03 RIU-1 respectively. The minimum detection limit is 0.277 RIU. The proposed sensor exhibits the highest sensitivity of 255 GHz/RIU at the optimum condition which is comparably higher than previously published papers on biosensors. The proposed design with its highest sensitivity and good detection parameters can be helpful in detecting waterborne bacteria.