Limits...
Multilayer hexagonal silicon forming in slit nanopore.

He Y, Li H, Sui Y, Qi J, Wang Y, Chen Z, Dong J, Li X - Sci Rep (2015)

Bottom Line: The results clearly show that the system undergoes an obvious transition from liquid to multilayer hexagonal film with the decrease of temperature, accompanied by dramatic change in potential energy, atomic volume, coordination number and lateral radial distribution function.Moreover, it is found that the quenching rate and slit size are of vital importance to the freezing structure of silicon film.The results also indicate that the slit nanopore induces the layering of liquid silicon, which further induces the slit size dependent solidification behavior of silicon film with different electrical properties.

View Article: PubMed Central - PubMed

Affiliation: School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou, 221116, People's Republic of China.

ABSTRACT
The solidification of two-dimensional liquid silicon confined to a slit nanopore has been studied using molecular dynamics simulations. The results clearly show that the system undergoes an obvious transition from liquid to multilayer hexagonal film with the decrease of temperature, accompanied by dramatic change in potential energy, atomic volume, coordination number and lateral radial distribution function. During the cooling process, some hexagonal islands randomly appear in the liquid first, then grow up to grain nuclei, and finally connect together to form a complete polycrystalline film. Moreover, it is found that the quenching rate and slit size are of vital importance to the freezing structure of silicon film. The results also indicate that the slit nanopore induces the layering of liquid silicon, which further induces the slit size dependent solidification behavior of silicon film with different electrical properties.

No MeSH data available.


Density distribution functions along the confined direction of the liquid and solid silicon for different slit sizes.(a) 1800 K (liquid); (b) 300 K(solid).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4593175&req=5

f9: Density distribution functions along the confined direction of the liquid and solid silicon for different slit sizes.(a) 1800 K (liquid); (b) 300 K(solid).

Mentions: In order to clarify the reasons for such the slit size dependent solidification behavior of silicon film, we have plotted the density distribution functions along the confined direction for the liquid (1800 K) and solid (300 K) silicon in Fig. 9. The results clearly suggest a structural correlation between the liquid and solid silicon. At D = 11 Å, 13.2 Å and 15.9 Å, the density distribution functions of the liquid and solid silicon both have two, three and four peaks as shown Fig. 9, indicating the two phases are both composed of two, three and four atomic layers, although the density peaks of liquid silicon are rather smooth than that of the solid one. At D = 12.3 Å, each main density peak of the liquid silicon split into two subpeaks, which becomes more obvious in the solid silicon corresponding to the buckled hexagonal structure. Based on the above, one can draw a conclusion that the structural difference of silicon film has already appeared before solidification and the layer number is determined by the slit size. With the decreasing temperature, the layering phenomenon is increasingly evident. This result is in good agreement with previous experimental and numerical studies that confined liquid undergoes a layering transition nearing the solid wall293031. Therefore, it can be deduce that the slit nanopore induces the layering of liquid silicon, which further induces the slit size dependent solidification behavior of silicon film.


Multilayer hexagonal silicon forming in slit nanopore.

He Y, Li H, Sui Y, Qi J, Wang Y, Chen Z, Dong J, Li X - Sci Rep (2015)

Density distribution functions along the confined direction of the liquid and solid silicon for different slit sizes.(a) 1800 K (liquid); (b) 300 K(solid).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4593175&req=5

f9: Density distribution functions along the confined direction of the liquid and solid silicon for different slit sizes.(a) 1800 K (liquid); (b) 300 K(solid).
Mentions: In order to clarify the reasons for such the slit size dependent solidification behavior of silicon film, we have plotted the density distribution functions along the confined direction for the liquid (1800 K) and solid (300 K) silicon in Fig. 9. The results clearly suggest a structural correlation between the liquid and solid silicon. At D = 11 Å, 13.2 Å and 15.9 Å, the density distribution functions of the liquid and solid silicon both have two, three and four peaks as shown Fig. 9, indicating the two phases are both composed of two, three and four atomic layers, although the density peaks of liquid silicon are rather smooth than that of the solid one. At D = 12.3 Å, each main density peak of the liquid silicon split into two subpeaks, which becomes more obvious in the solid silicon corresponding to the buckled hexagonal structure. Based on the above, one can draw a conclusion that the structural difference of silicon film has already appeared before solidification and the layer number is determined by the slit size. With the decreasing temperature, the layering phenomenon is increasingly evident. This result is in good agreement with previous experimental and numerical studies that confined liquid undergoes a layering transition nearing the solid wall293031. Therefore, it can be deduce that the slit nanopore induces the layering of liquid silicon, which further induces the slit size dependent solidification behavior of silicon film.

Bottom Line: The results clearly show that the system undergoes an obvious transition from liquid to multilayer hexagonal film with the decrease of temperature, accompanied by dramatic change in potential energy, atomic volume, coordination number and lateral radial distribution function.Moreover, it is found that the quenching rate and slit size are of vital importance to the freezing structure of silicon film.The results also indicate that the slit nanopore induces the layering of liquid silicon, which further induces the slit size dependent solidification behavior of silicon film with different electrical properties.

View Article: PubMed Central - PubMed

Affiliation: School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou, 221116, People's Republic of China.

ABSTRACT
The solidification of two-dimensional liquid silicon confined to a slit nanopore has been studied using molecular dynamics simulations. The results clearly show that the system undergoes an obvious transition from liquid to multilayer hexagonal film with the decrease of temperature, accompanied by dramatic change in potential energy, atomic volume, coordination number and lateral radial distribution function. During the cooling process, some hexagonal islands randomly appear in the liquid first, then grow up to grain nuclei, and finally connect together to form a complete polycrystalline film. Moreover, it is found that the quenching rate and slit size are of vital importance to the freezing structure of silicon film. The results also indicate that the slit nanopore induces the layering of liquid silicon, which further induces the slit size dependent solidification behavior of silicon film with different electrical properties.

No MeSH data available.