Donor effect dominated molybdenum disulfide/graphene nanostructure-based field-effect transistor for ultrasensitive DNA detection.

Field effect transistor (FET) biosensors based on low-dimensional materials have the advantages of small in size, simple structure, fast response and high sensitivity. In this work, a field-effect transistor biosensor based on molybdenum disulfide/graphene (MoS2/graphene) hybrid nanostructure was proposed and fabricated for DNA hybridization detection. The biosensor achieved an effective response to DNA concentrations in a broad range from 10 aM to 100 pM and a limit of detection (LOD) of 10 aM was obtained, which was one or more orders of magnitude lower than the reported result. The sensing mechanisms (donor and gating effects) of the FET sensor were discussed. A larger voltage shift of the charge neutral point was obtained due to a strengthened donor effect and a weakened gating effect caused by the introduction of MoS2 layers. Such FET sensor shows high specificity for different matching degrees of complementary DNA, indicating the potential use of such a sensor in disease diagnosis.