Quaternary 2D monolayer CuClSeHg: anisotropic carrier mobility and tunable bandgap for transistor and photocatalytic applications.

Despite the advantages of quaternary two-dimensional (2D) materials, fewer studies have been done on them than binary 2D materials. Calculations of quaternary 2D monolayer CuClSeHgbased on density functional theory and Green's function surface analysis provide insights into its structural, dynamic, and thermal stability. This material has a direct band gap of 0.91/2.0 eV (Perdew-Burke-Ernzerhof/Heyd-Scuseria-Ernzerhof) and demonstrates anisotropic carrier mobility. The electron mobility in thedirection is 1.2 × 10cmVs, which is significantly higher than the hole mobility of 0.48 × 10cmVs. In thedirection, the electron mobility is 1.01 × 10cmVsand is 8.9 times larger than the hole mobility of 0.11 × 10cmVs. The light absorption coefficients of CuClSeHgare 1.0 × 10cmand 2.5 × 10cmin the visible and ultraviolet ranges, respectively. Uniaxial strain leads to an anisotropic alteration in the band gap and band edge position. By manipulating the strain direction and level in CuClSeHg, it is possible to increase the current ON/OFF ratio for field-effect transistors (FETs) and to facilitate photocatalytic water splitting through a redox reaction. The research reveals that CuClSeHg, a 2D monolayer in the quaternary form, has promising capabilities as an alternative for creating crystal-oriented FETs and photocatalytic water splitting systems.