Publication Date

2011

Document Type

Thesis

Committee Members

Amir Farajian (Advisor), Sharmila Mukhopadhyay (Committee Member), Raghavan Srinivasan (Committee Member)

Degree Name

Master of Science in Engineering (MSEgr)

Abstract

Nanosensors, i.e., sensors based on nanomaterials, have the potential of superior performance owing to their size effect, and can have significant effects on detection of pollutants in the environment. Various nanowires have been used in this context. Here we investigate the possibility of NO2 and Li detection using the quantum conductance change in graphene nanoribbon. Quantum conductance modification in graphene nanoribbon upon NO2/Li adsorption was calculated using ab initio methods. The optimized structures of the adsorbed NO2 indicated two different geometries where either nitrogen or oxygen was closer to the graphene lattice. The former resulted in charge transfer from NO2 to graphene, while the latter caused charge to be transferred in the reverse direction. As for Li, the optimized adsorption location was at the zigzag edge and above the center of a hexagon (hollow site). The charge transfer in the Li case was smaller compared to the NO2 case. The quantum conductance calculations for NO2 adsorption showed semiconductor-to-metal transformation and gap modification for the two adsorption geometries. In the case of Li adsorption, the gap remained almost the same as that of pristine graphene nanoribbon, however, the pseudo-gap was widened upon Li adsorption. These effects are detectable and explain the basis for nanosensor effect in graphene nanoribbons, with superior sensitivity and selectivity

Page Count

59

Department or Program

Department of Mechanical and Materials Engineering

Year Degree Awarded

2011


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