Tetragonal graphene nanodot as carbon monoxide gas sensor and current rectification device

In this theoretical work, we have explored the utilities of non-toxic boron (B)-nitrogen (N) pair substitution on tetragonal graphene (T-graphene/TG) nanodot in CO gas sensing. Within the realm of first-principles calculations, we have identified the two possible doping sites of B-N pair suitable for CO molecule adsorption. This adsorption process not only stabilizes the systems but also enhances the magnitude of the dipole moments because of the redistribution of charges. The existence of CO molecule on the adsorbent surface has been characterized with the help of room temperature Raman fingerprints. It is observed that low intense CO stretching mode at 2123.35 cm−1 gets softened after adsorption. The presence of CO molecule even enhances the conductivity of the systems. As a consequence, the tunneling current calculation based on self ensemble metal-system-metal junction via Landauer's formalism has been invoked and the calculations reveal that the systems can behave as current rectifier and Zener diode under suitable parametric values. Therefore, it is expected that this first principles study will shed light for fabricating nanosensors and rectifiers using B-N functionalized TG nanodot.