Strain-tunable borophene island single electronic nanosensor with quantised detection resolution

Borophene, with its anisotropic electronic structure and high surface sensitivity, offers a promising two-dimensional platform for nanoscale sensing applications. In this work, we designed and investigated strain-engineered α and β-borophene island based single electron transistor (SET) devices for the detection of inorganic gas molecules using first-principles based calculations combined with non-equilibrium Green's function formalism. The influence of tensile and compressive strain on the electrostatic operation, charging energy, switching voltage and charge stability characteristics of the device were systematically examined. The results show that strain effectively modulates the SET transport response and reduces the charging energy, indicating the possibility of low-power operation at elevated temperatures. The adsorption of inorganic gas molecules on borophene islands produces molecule-specific changes in adsorption energy, charge transfer, switching voltage and differential conductance. Distinct shifts in the line scans of charge stability diagrams provide clear signatures for identifying individual gas molecules. These findings demonstrate that straintunable borophene SETs can serve as sensitive and selective nanosensors for inorganic and toxic gas detection with single molecular detection resolution.