A theoretical prediction of novel Janus NiSX (X = O, Se, Te) Monolayers: Electronic, optical, and thermoelectric properties

Using density functional theory and semi-classical Boltzmann transport theory were employed to investigate the electronic structure, phononic and optical properties, dynamic stability, and thermoelectric characteristics of Janus NiSX (X = O, Se, Te). The electronic band structure of NiSTe indicates metallic behavior while NiSO and NiSSe show semiconducting features with indirect bandgap. Phononic properties and dynamic stability analyses reveal the stability of Janus Ni compounds. These compounds can be utilized as promising wave reflectors in the infrared (IR) range. Moreover, NiSO and NiSSe are good optical absorbers in the range of far ultraviolet (FUV). NiSTe exhibits isotropic absorption in the visible as well as FUV ranges. Thermoelectric calculations at room temperature show high Seebeck coefficients of 650 and 550 mu V/K for NiSO and NiSSe, respectively. The large power factor of 20.83 x 10(10) and 25.16 x 10(10) W/msK(2) are respectively found for n-type NiSO and NiSSe. The results suggest NiSO and NiSSe as promising thermoelectric materials with figure of merit of one (ZT similar to 1). Consequently, NiSO and NiSSe can serve as efficient alternatives to conventional thermoelectric devices. The results of the current research can be used in the design of novel nanoelectronic devices as well as providing an excellent database for future studies.

Automated summary

Density functional theory and semi-classical Boltzmann transport theory were used to investigate the properties of Janus NiSX (X = O, Se, Te), including electronic structure, phononic and optical properties, dynamic stability, and thermoelectric characteristics. The results showed that NiSTe has metallic behavior, while NiSO and NiSSe are semiconducting with indirect bandgap. Janus Ni compounds were found to be stable based on phononic properties and dynamic stability analyses. NiSO and NiSSe have potential as wave reflectors in the infrared range and good optical absorbers in the far ultraviolet range. NiSO and NiSSe also exhibited high Seebeck coefficients and power factors, making them promising thermoelectric materials with a figure of merit of one (ZT similar to 1). These findings suggest that NiSO and NiSSe can be used as efficient alternatives in thermoelectric devices.