Effect of molecular functionalization in carbon nanotube and graphene nanoribbon based atomic scale sensors

Abstract

Abstract Advancement in fabrication technologies has led to the possibility for synthesizing atomic scale structures of graphene nanoribbon (GNR) and carbon nanotube (CNT). The purpose of this paper is to model the electronic property and electrical characteristics of these structures by atomistic modelling using non-equilibrium Green’s function (NEGF) and compare the effect of molecular functionalization and sensing. Within drain to source bias voltage of 1 Volts, armchair configuration based GNR (AGNR) is not found to be sensitive to functionalized molecule with lesser alteration in the density of states (DoS) and transmission spectra. Rolling of the AGNR into armchair CNT (ACNT) makes the performance worse and more insensitive. However, changing the configuration of GNR from armchair to zigzag shows remarkable alteration in the DoS and transmission spectra and significant improvement in sensitivity. This improves further on rolling the zigzag GNR (ZGNR) to zigzag CNT (ZCNT). However, this variation in sensitivity is found to fall with increase in width to length (W/L) ratio of the nanostructures. This specifies the importance of smaller atomic structures and the work provides a guideline for effectively utilization these structures for bio and chemosensing.