Study of electronic structure of graphene nanomesh with variable pore size / Sarah Gamal Ahmed Abouelhasab ; Supervised Lobna Mohamed Salah , Hoda Aboushady , Walaa M. Seif

Thesis (M.Sc.) - Cairo University - Faculty of Science - Department of Physics

Graphene nanomeshes (GNMs) are novel materials that recently raised a lot of interest. They are fabricated by forming a lattice of pores in graphene. Depending on the pore size and pore lattice constant, GNMs can be either semimetallic or semiconducting with a gap large enough ( 0.5 eV) to be considered for transistor applications. The fabrication process is bound to produce some structural disorder due to variations in pore sizes. Recent electronic transport measurements in GNM devices show a degradation of their bandgap in devices having pore-size disorder. It is therefore important to understand the e ect of such variability on the electronic properties of semiconducting GNMs. In this work we use the density functional-based tight binding formalism to calculate the electronic properties of GNM structures with di erent pore sizes, pore densities, and with hydrogen and oxygen pore edge passivations We nd that structural disorder reduces the electronic gap and the carrier group velocity, which may interpret recent transport measurements in GNM devices. Furthermore the trend of the bandgap with structural disorder is not signi cantly a ected by the change in pore edge passivation. Our results show that even with structural disorder, GNMs are still attractive from a transistor device perspective

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