Modeling optical properties of silicon clusters by first principles: From a few atoms to large nanocrystals

Journal Article · Tue Apr 21 00:00:00 EDT 2015 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4918588· OSTI ID:22415687

Nurbawono, Argo; Liu, Shuanglong ^[1]; Zhang, Chun ^[1]

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1. Department of Physics and the Centre for Advanced 2D Materials, National University of Singapore, 2 Science Drive 3 (Singapore)

Time dependent density functional tight binding (TDDFTB) method is implemented with sparse matrix techniques and improved parallelization algorithms. The method is employed to calculate the optical properties of various Si nanocrystals (NCs). The calculated light absorption spectra of small Si NCs from TDDFTB were found to be comparable with many body perturbation methods utilizing planewave basis sets. For large Si NCs (more than a thousand atoms) that are beyond the reach of conventional approaches, the TDDFTB method is able to produce reasonable results that are consistent with prior experiments. We also employed the method to study the effects of surface chemistry on the optical properties of large Si NCs. We learned that the optical properties of Si NCs can be manipulated with small molecule passivations such as methyl, hydroxyl, amino, and fluorine. In general, the shifts and profiles in the absorption spectra can be tuned with suitably chosen passivants.

• OSTI ID: 22415687
• Journal Information: Journal of Chemical Physics, Vol. 142, Issue 15; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ABSORPTION SPECTRA
ALGORITHMS
ATOMS
CHEMISTRY
COMPARATIVE EVALUATIONS
DENSITY FUNCTIONAL METHOD
FLUORINE
HYDROXIDES
MANY-BODY PROBLEM
MOLECULES
NANOSTRUCTURES
OPTICAL PROPERTIES
PASSIVATION
PERTURBATION THEORY
SILICON
SURFACES
TIME DEPENDENCE
VISIBLE RADIATION