The abstract reads: "The authors present a study on the evolution behaviors of the transfer characteristics of MoS2 and WSe2 field-effect transistor biosensors when they are subjected to tumor necrosis factor-alpha and streptavidin solutions with varying analyte concentrations. Both MoS2 and WSe2sensors exhibit very low detection limits (∼60 fM for tumor necrosis factor-alpha detection; ∼70 fM for streptavidin detection). However, WSe2 sensors exhibit the higher linear-regime sensitivities in comparison with MoS2 sensors. In particular, WSe2 sensors exhibit high linear-regime sensitivities up to ∼1.54%/fM for detecting streptavidin at a concentration of ∼70 fM. Such relatively higher sensitivities obtained from WSe2 sensors are attributed to their intrinsic ambipolar transfer characteristics, which make their ON-state carrier concentrations significantly lower than those of MoS2 sensors, and therefore, the target-molecule-induced doping effect results in more prominent channel conductance modulation in WSe2 transistor sensors than in MoS2 sensors.Furthermore, this work strongly implies that the target-molecule-induced surface scattering also plays an important role in determining the response behaviors of the sensors made from atomically layered materials. Especially, the competition between target-molecule-induced p-doping and surface-scattering effects is responsible for the sensor behavior variation observed in the p-type conduction branch of WSe2 sensors. This work advances the critical device physics highly relevant with the fabrication and implementation of reliable nanoelectronic biosensorsbased on emerging atomically layered semiconductors."
Read the full article here: http://scitation.aip.org/content/avs/journal/jvstb/33/6/10.1116/1.4930040