Electronic and optical properties of monolayer InSe quantum dots

Abstract

The novel two-dimensional (2D) semiconductor, InSe, with tunable band gap and high electron mobility, has attracted increasing research interest. In this work, we demonstrate theoretically the strong geometry confinement in InSe quantum dots (QD) and manipulate their electronic and optical properties using QD shape and external field. The electronic energy levels, density of states, probability density of states and magneto-optical absorption spectra, are calculated by utilizing the tight-binding method with Coulomb interaction in the Hubbard model. In contrast to other 2D materials, e.g. phosphorene, InSe-QDs exhibit distinct features as (a) edge states appear in the bottom of the conduction band regardless of the shapes of InSe-QDs; (b) the edge states are mainly provided by the In atoms at the both armchair and zigzag edges in InSe-QDs; (c) optical gap is distinct from band gap. The rectangular InSe-QDs produce anisotropic optical absorption spectra, whereas hexagonal and triangular InSe-QDs produce isotropic absorption spectra. The applied magnetic field would weaken this anisotropy.

Electric-field-controlled electronic structures and quantum transport in monolayer InSe nanoribbons

“…For the 2D MX nanoribbons, density functional theory (DFT) calculations show that their electronic structures and magnetic properties of are very sensitive to the edge types [38], edge hydrogenation [39,40], and edge reconstruction [41]. In addition, the tight-binding calculations demonstrate that edge states appear in InSe quantum dots regardless of the their shapes and edge types [42]. Although great progress has been made in the study of MX nanostructures, a deep investigation on their electronic structures and quantum transport modulation is still lacked.…”