# First-principle study of quantum confinement effect on small sized silicon quantum dots using density-functional theory

## Abstract

Density functional theory (DFT), as a first-principle approach has successfully been implemented to study nanoscale material. Here, DFT by numerical basis-set was used to study the quantum confinement effect as well as electronic properties of silicon quantum dots (Si-QDs) in ground state condition. Selection of quantum dot models were studied intensively before choosing the right structure for simulation. Next, the computational result were used to examine and deduce the electronic properties and its density of state (DOS) for 14 spherical Si-QDs ranging in size up to ∼ 2 nm in diameter. The energy gap was also deduced from the HOMO-LUMO results. The atomistic model of each silicon QDs was constructed by repeating its crystal unit cell of face-centered cubic (FCC) structure, and reconstructed until the spherical shape obtained. The core structure shows tetrahedral (T{sub d}) symmetry structure. It was found that the model need to be passivated, and hence it was noticed that the confinement effect was more pronounced. The model was optimized using Quasi-Newton method for each size of Si-QDs to get relaxed structure before it was simulated. In this model the exchange-correlation potential (V{sub xc}) of the electrons was treated by Local Density Approximation (LDA) functional and Perdew-Zungermore »

- Authors:

- School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor (Malaysia)

- Publication Date:

- OSTI Identifier:
- 22308307

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: AIP Conference Proceedings; Journal Volume: 1614; Journal Issue: 1; Conference: 2014 UKM FST postgraduate colloquium, Selangor (Malaysia), 9-11 Apr 2014; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; APPROXIMATIONS; CRYSTALS; DENSITY FUNCTIONAL METHOD; ELECTRONS; FCC LATTICES; GROUND STATES; NEWTON METHOD; POTENTIALS; QUANTUM DOTS; SILICON; SPHERICAL CONFIGURATION

### Citation Formats

```
Anas, M. M., Othman, A. P., and Gopir, G..
```*First-principle study of quantum confinement effect on small sized silicon quantum dots using density-functional theory*. United States: N. p., 2014.
Web. doi:10.1063/1.4895180.

```
Anas, M. M., Othman, A. P., & Gopir, G..
```*First-principle study of quantum confinement effect on small sized silicon quantum dots using density-functional theory*. United States. doi:10.1063/1.4895180.

```
Anas, M. M., Othman, A. P., and Gopir, G.. Wed .
"First-principle study of quantum confinement effect on small sized silicon quantum dots using density-functional theory". United States.
doi:10.1063/1.4895180.
```

```
@article{osti_22308307,
```

title = {First-principle study of quantum confinement effect on small sized silicon quantum dots using density-functional theory},

author = {Anas, M. M. and Othman, A. P. and Gopir, G.},

abstractNote = {Density functional theory (DFT), as a first-principle approach has successfully been implemented to study nanoscale material. Here, DFT by numerical basis-set was used to study the quantum confinement effect as well as electronic properties of silicon quantum dots (Si-QDs) in ground state condition. Selection of quantum dot models were studied intensively before choosing the right structure for simulation. Next, the computational result were used to examine and deduce the electronic properties and its density of state (DOS) for 14 spherical Si-QDs ranging in size up to ∼ 2 nm in diameter. The energy gap was also deduced from the HOMO-LUMO results. The atomistic model of each silicon QDs was constructed by repeating its crystal unit cell of face-centered cubic (FCC) structure, and reconstructed until the spherical shape obtained. The core structure shows tetrahedral (T{sub d}) symmetry structure. It was found that the model need to be passivated, and hence it was noticed that the confinement effect was more pronounced. The model was optimized using Quasi-Newton method for each size of Si-QDs to get relaxed structure before it was simulated. In this model the exchange-correlation potential (V{sub xc}) of the electrons was treated by Local Density Approximation (LDA) functional and Perdew-Zunger (PZ) functional.},

doi = {10.1063/1.4895180},

journal = {AIP Conference Proceedings},

number = 1,

volume = 1614,

place = {United States},

year = {Wed Sep 03 00:00:00 EDT 2014},

month = {Wed Sep 03 00:00:00 EDT 2014}

}