Structures, stabilities and electronic properties of graphdiyne nanoribbons

Abstract

The one-dimensional graphdiyne nanoribbons are studied using the self-consistent field crystal orbital method based on density functional theory in this paper. The structures, stabilities, electronic, elastic and transport properties of these nanoribbons with different edges and widths are investigated. These graphdiyne strips can be obtained from cutting the graphdiyne sheet or the carbomerization of the graphene strips. It is found that the carbomerization not only expands the structures, but also alters the stabilities, electronic, elastic and transport properties of the original systems. Here the graphdiyne nanoribbons studied are all more stable than the graphdiyne monolayer in the view of energy. Different from the graphene nanoribbons, the graphdiyne strips are all semiconductors. According to our calculations, the band gaps of the graphdiyne strips decrease monotonically as the widths increase. A quantitative relation between the band gaps and the widths of the graphdiyne nanoribbons is obtained. Moreover, we also calculate the mobilities of charge carriers for these strips based on the deformation potential theory and effective mass approach. The calculated mobilities are in the range of 10²–10⁶ cm² V⁻¹s⁻¹ at room temperature. The relationship between mobilities and nanoribbon widths is different for electron and hole charge carriers. The mobilities of electrons are always larger than those of holes for these graphdiyne nanoribbons studied. Hence, the graphdiyne strips are possibly more favorable for electron transportation.