Gate-assisted MoSe2 transistor to detect the streptavidin via supporter molecule engineering

Atomically thin two-dimensional (2D) transition metal dichalcogenide (TMDC) semiconductor materials have garnered significant attention due to their remarkable properties surpassing conventional metal-oxide semiconductors. These properties include high carrier mobility, adjustable bandgaps, and exceptional sensitivity, providing them with tremendous potential for various applications. The remarkable characteristics of these 2D semiconductor materials led to fabricating of atomically thin electronic devices including diodes, photodetectors, memristors, and biosensors. Here, we present an atomically thin transistor composed of n-type molybdenum di-selenide (n-MoSe2), exhibiting a large reverse current. The charge transport through the MoSe2 transistor is modulated via back gate voltage, studied at various basing and gate voltages. Finally, the MoSe2 transistor device is utilized as a biosensor to detect the protein (streptavidin) as target analyte at fixed biasing and gate voltages. Using our designed pyrene-based supporter molecule, which is stacked over the MoSe2 surface via π-π stacking, the target protein is identified while avoiding any screening effects like Debye screening. Additionally, the real-time response of the biosensing device is recorded while maintaining a constant biasing voltage of 0.5 V, covering a range of streptavidin concentrations down to the lowest detectable concentration of 1 pM. Such utilization of the MoSe2 device as a biosensor could pave the way for manufacturing cutting-edge electrical devices which can detect a broad range of biomolecules, such as DNA (like ct-DNA) and the COVID-19 spike protein.