TITLE:
Ab Initio Molecular Orbital Calculation for Optical and Electronic Properties Evaluation of Small and Medium Size Silicon Nano-Clusters Found in Silicon Rich Oxide Films
AUTHORS:
Néstor David Espinosa Torres, José Francisco Javier Flores Gracia, José Alberto Luna López, Juan Carlos Ramírez García, Alfredo Morales Sánchez, José Luis Sosa Sánchez, David Hernández de la Luz, Francisco Morales Morales
KEYWORDS:
Nano-Crystals; Silicon Clusters; Silicon-Rich Oxide; Luminescence; Magic-Number
JOURNAL NAME:
Journal of Modern Physics,
Vol.4 No.11B,
November
29,
2013
ABSTRACT: In systems in atomic and nano scales such as clusters or
agglomerates constituted of particles from a few to less than one hundred of
atoms, quantum confinement effects are very important. Their optical and
electronic properties are often dependent on the size of the systems and the
way in which the atoms in these clusters are bonded. Generally, these nano-structures
display optical and electronic properties significantly different of those
found in corresponding bulk materials. Silicon agglomerates found in Silicon
Rich Oxide (SRO) films have optical properties, which have reported as depended directly on nano-crystal size. Furthermore, the room temperature
photoluminescence (PL) of Silicon Rich Oxides (SRO) has repeatedly generated a
huge interest due to their possible applications in optoelectronic devices.
However, a plausible emission mechanism has not yet widespread acceptance of
the scientific community. In this research, we employed the Density Functional
Theory with a functional B3LYP and a basis set 6 - 31G* to
calculate the optical and electronic properties of small (six to ten silicon
atoms) and medium size clusters of silicon (constituted of eleven to fourteen
silicon atoms). With the theoretical calculation of the structural and optical
properties of silicon clusters, it is possible to evaluate the contribution of
silicon agglomerates in the luminescent emission mechanism experimentally found
in thin SRO films.