Influence of biaxial strain on the structural, electronic, optical and thermoelectric properties of the AMoGeN2 (A=S, Se) monolayer: A first-principles investigation

In order to overcome the global energy crisis and utilize wasted heat as a useful energy resource, thermoelectric materials have gain much attention. Currently, the structural properties of AMoGeN2 (A=S, Se) monolayers are investigated and further, to confirm the stability of these materials, we have calculated their cohesive energies and phonon spectra. Also, the electronic properties are explored in strain free and strained environment. These materials have indirect band gap semiconducting nature, and their band gaps are tuned using biaxial compressive and tensile strain. The electronic bandgap values are 2.00 eV to 0.57 eV (without SOC) and 2.21 eV to 1.37 eV (with SOC) with strain from +6 % to -6% for the case of SMoGeN2 whereas 1.66 eV to 0.65 eV (without SOC) and 1.75 eV to 0.82 eV (with SOC) with strain from +6 % to -6% for SeMoGeN2 monolayers respectively. The optical properties confirm the interaction of these materials with a wide range of light spectrum at different strain with the observation of peaks in the infrared and visible regions. Coupled with these attractive optical aspects, the significant values of Seebeck coefficients and power factors reveal that layered materials AMoGeN2 (A=S, Se) will be promising optoelectronic and thermoelectric materials.