First principles study on thickness dependent structural and electronic properties unveiling the growth and stability of 2D layered II–VI semiconducting compounds

Abstract

By employing first principles density functional theory calculations on thickness dependent structural and electronic properties of (0001) surface slabs of wurtzite MX compounds, our study demonstrated the possibility of existence...

First-Principles Study on Lithium Intercalation in Traditional Semiconductors Leading to Investigation of Structural Stability and Thermoelectric Properties of Their 2D Structures

“…For 2D layers, three independent elastic constants, such as C 11 , C 22 , and C 66 , are calculated and reported in Table S6. These values for the 2d system are consistent with previous theoretical values. ,,− For stable layers, it must obey the following mechanical stability according to Born’s criteria C 11 C 22 –C 12 2 > 0 and C 66 > 0. All 2D systems satisfy this criterion, indicating the mechanical stability of the system.…”

“…), graphene-like buckled 2D materials (silicene, germanene, arsenene, phosphorene, tinene, antimonene, etc. ), transition metal dichalcogenides (TMDs), and layered semiconductors that are being explored at the current moment. − Recently groups II–IV, III–V, and IV–IV semiconductors have been drawing incredible research interest due to their promising electronic and optical properties. − …”

Restoring Piezoelectric Properties in 2D Zinc Oxide Nanosheets by Surface Modifications: Implications for Piezoelectric Nanogenerators

“…We did perform calculations on a 12-layer sheet and showed that it is more stable in the wurtzite form and had a piezoelectric constant of 0.92 C/m 2 , which is 89% of the bulk value. Our findings agree with previous work, which showed that ZnO becomes buckled after 7- 16,17 or 10-15 layers. This is consistent with the structure preferring to be buckled, instead of graphitic, as it was for the thinner sheets.…”

“…Claeyssens et al showed using computational methods that ZnO nanosheets terminated by the polar (0001) and (0001̅) surfaces and having 18-layers or less flatten upon relaxation, becoming graphitic-like in structure up to 10-layers thick. Zhao et al and Devi et al also showed using density functional theory (DFT) calculations that ZnO sheets are flat up to a thickness of 7-layers. As a result of this flattening of the layers, the sheets lose their piezoelectric properties as the dipole moment from the buckled (0001) and (0001̅) surfaces no longer exists, meaning ultrathin ZnO nanosheets are not suitable for piezoelectric nanogenerators.…”

“…Claeyssens et al 15 showed using computational methods that ZnO nanosheets terminated by the polar (0001) and (0001̅ ) surfaces and having 18-layers or less flatten upon relaxation, becoming graphitic-like in structure up to 10layers thick. Zhao et al 16 and Devi et al 17 flattening of the layers, the sheets lose their piezoelectric properties as the dipole moment from the buckled (0001) and (0001̅ ) surfaces no longer exists, meaning ultrathin ZnO nanosheets are not suitable for piezoelectric nanogenerators. By supporting ZnO nanosheets on a SiO 2 substrate, it was shown that the buckling can be restored for sheets between 3and 8-layers thick, with a ∼1 nm (5-layer) sheet showing a piezoelectric response greater than the bulk.…”