Two-dimensional 2γ-In2Se3 in bilayer-like coloring triangle lattice: Mechanical, electronic, transport, and photocatalytic properties

Abstract

The discovery of two-dimensional (2D) materials derived from non-van der Waals (vdW) bulk counterparts has opened up a new era, drawing attention to the crystals composed of asymmetrically bonded vertical exotic layers. In this respect, gamma -In2Se3, a promising material utilized in various applications, built with coloring triangle layers, emerges as a suitable candidate. Through first-principles calculations, we show that a novel 2D structure, the 2 gamma -In2Se3 monolayer, consisting of a bilayer-like coloring triangle lattice, can be exfoliated from bulk gamma -In2Se3 with minimal external energy. The formation of this exotic 2D lattice is facilitated by sp3 hybrid bonds. Comprehensive phonon dispersion and finite-temperature molecular dynamics analyses confirm the thermodynamic stability of the 2 gamma -In2Se3 monolayer. The material exhibits an anisotropic mechanical response due to missing bonds at lattice sites, making it suitable for flexible nanoelectronic devices. It possesses semiconductor characteristics with an indirect band gap in the visible region. Analysis of band edge positions and charge carrier mobility suggests that the 2 gamma -In2Se3 monolayer is highly efficient for photocatalytic water-splitting applications.