Abstracts Book - IMRC 2018

• SF2-P061
DENSITY FUNCTIONAL STUDY OF [111]-Si NANOWIRES WITH
INTERSTITIAL Li AND Na ATOMS AS POTENTIAL ANODIC
MATERIALS
Alvaro Miranda 1 , Fernando Salazar 1 , Alejandro Trejo 1 , Eliel Carvajal Quiroz 1 , L. A. Pérez 2 , Miguel
Cruz Irrison 1
1 Instituto Politécnico Nacional - IPN, ESIME Culhuacan, Mexico. 2 Instituto de Física - Universidad
Nacional Autónoma de México, , Mexico.
In this work, we present a density functional study of the electronic and
mechanical properties of hydrogen passivated silicon nanowires (SiNWs) grown
along [111] crystallographic direction with a diameter around of 0.73 nm, and
considering two comparative cases, the SiNWs with interstitial sodium (Na) and
lithium (Li) atoms. For both systems, the concentration of interstitial atoms were
from 1 to 12 at different T d positions in the SiNW structure. The results show
that for the SiNWs with interstitial Li atoms, the Fermi energy shifts to the
conduction band, resulting in a metallic behavior, except for 6, 10 and 12 Li
atoms where the behavior is semiconductor. In contrast, the SiNWs with
interstitial Na atoms, the Fermi energy shifts to the conduction band only for
concentrations of 1 and 4 Na atoms, while for the others the behavior is
semiconductor and the size of the band gap is a function of the concentration
of Na atoms. This result indicates that the position of the interstitial Li and Na
atoms have a strong effect in the metallic or semiconductor behavior of the
SiNWs. On the other hand, the Youngs modulus for the SiNWs for both study
cases increases in comparison to the pure hydrogen passivated SiNWs, until a
critical concentration where its value diminishes indicating a structural
deterioration. This result indicates that there is a critical concentration where
the deformation of the SiNWs is in the elastic region and the structure tolerates
the presence of interstitial Li and Na atoms, then the SiNWs could be
incorporated as anodic materials with a better useful life when the
concentration of interstitial Li and Na atoms stays below their critical value.
Acknowledgment: This work was supported by IPN multidisciplinary projects
2018-1937, 2018-1941 and 2018-1969; PAPIIT-DGAPA-UNAM IN107717. The
computing resources were given for the Supercomputing department of
DGTIC-UNAM.
Keywords: Silicon Nanowires, Rechargable batteries, Youngs modulus
Presenting authors email: amirandad.ipn@gmail.com