Vacancy defected blue and black phosphorene nanoribbons as gas sensor of NOx and SOx molecules

Black phosphorene, due to its high chemical activity and large surface-to-volume ratio, indicates potential application for gas sensing. Additionally, recently synthesized blue phosphorene has attracted a lot of attention because of its properties, appropriate for applications in different fields. In this work, the sensing properties of vacancy defected black and blue phosphorene nanoribbons for NOx and SOx molecules are analyzed with density functional theory. Adsorption energy and adsorbate/phosphorene distance are studied for sensing molecules on pristine black/blue phosphorene nanoribbons which show the sensing capability of these materials. In order to further develop the sensor performance, considering the vacancy defect in the host material is suggested. Due to comprehensively analysing the effect of vacancy defect in the terms of sensor response, the I-V characteristics of defected blue/black phosphorene-based FET structures are calculated. Calculation results confirm that, vacancy defect increases the adsorption energies of all examined molecules on phosphorene-based substrates but calculated I-V values show small changes in current responses of armchair black/blue phosphorene nanoribbons in both pristine and defected forms. However, in the case of zigzag phosphorene nanoribbons, great current modifications before and after sensing process are obtained. Consequently, our results present a promising application of vacancy defected zigzag phosphorene nanoribbon in gas sensing.