### 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 (Td) 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 (Vxc) of the electrons was treated by Local Density Approximation (LDA) functional and Perdew-Zunger (PZ) functional.

Original language | English |
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Title of host publication | 2014 UKM FST Postgraduate Colloquium - Proceedings of the Universiti Kebangsaan Malaysia, Faculty of Science and Technology 2014 Postgraduate Colloquium |

Editors | Zahari Ibrahim, Haja Maideen Kader Maideen, Nazlina Ibrahim, Nurul Huda Abd Karim, Taufik Yusof, Fatimah Abdul Razak, Nurulkamal Maseran, Rozida Mohd Khalid, Noor Baa'yah Ibrahim, Hasidah Mohd. Sidek, Mohd Salmi Md Noorani, Norbert Simon |

Publisher | American Institute of Physics Inc. |

Pages | 104-109 |

Number of pages | 6 |

ISBN (Electronic) | 9780735412507 |

DOIs | |

Publication status | Published - 1 Jan 2014 |

Event | 2014 Postgraduate Colloquium of the Universiti Kebangsaan Malaysia, Faculty of Science and Technology, UKM FST 2014 - Selangor, Malaysia Duration: 9 Apr 2014 → 11 Apr 2014 |

### Publication series

Name | AIP Conference Proceedings |
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Volume | 1614 |

ISSN (Print) | 0094-243X |

ISSN (Electronic) | 1551-7616 |

### Other

Other | 2014 Postgraduate Colloquium of the Universiti Kebangsaan Malaysia, Faculty of Science and Technology, UKM FST 2014 |
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Country | Malaysia |

City | Selangor |

Period | 9/4/14 → 11/4/14 |

### Fingerprint

### Keywords

- Density functional theory (DFT)
- DOS plot
- HOMO-LUMO gap
- LDA-PZ
- Quantum dots (QDs)

### ASJC Scopus subject areas

- Physics and Astronomy(all)

### Cite this

*2014 UKM FST Postgraduate Colloquium - Proceedings of the Universiti Kebangsaan Malaysia, Faculty of Science and Technology 2014 Postgraduate Colloquium*(pp. 104-109). (AIP Conference Proceedings; Vol. 1614). American Institute of Physics Inc.. https://doi.org/10.1063/1.4895180

**First-principle study of quantum confinement effect on small sized silicon quantum dots using density-functional theory.** / Anas, M. M.; Othman, A. P.; Gopir, Geri Kibe.

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

*2014 UKM FST Postgraduate Colloquium - Proceedings of the Universiti Kebangsaan Malaysia, Faculty of Science and Technology 2014 Postgraduate Colloquium.*AIP Conference Proceedings, vol. 1614, American Institute of Physics Inc., pp. 104-109, 2014 Postgraduate Colloquium of the Universiti Kebangsaan Malaysia, Faculty of Science and Technology, UKM FST 2014, Selangor, Malaysia, 9/4/14. https://doi.org/10.1063/1.4895180

}

TY - GEN

T1 - First-principle study of quantum confinement effect on small sized silicon quantum dots using density-functional theory

AU - Anas, M. M.

AU - Othman, A. P.

AU - Gopir, Geri Kibe

PY - 2014/1/1

Y1 - 2014/1/1

N2 - 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 (Td) 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 (Vxc) of the electrons was treated by Local Density Approximation (LDA) functional and Perdew-Zunger (PZ) functional.

AB - 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 (Td) 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 (Vxc) of the electrons was treated by Local Density Approximation (LDA) functional and Perdew-Zunger (PZ) functional.

KW - Density functional theory (DFT)

KW - DOS plot

KW - HOMO-LUMO gap

KW - LDA-PZ

KW - Quantum dots (QDs)

UR - http://www.scopus.com/inward/record.url?scp=84946901730&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84946901730&partnerID=8YFLogxK

U2 - 10.1063/1.4895180

DO - 10.1063/1.4895180

M3 - Conference contribution

T3 - AIP Conference Proceedings

SP - 104

EP - 109

BT - 2014 UKM FST Postgraduate Colloquium - Proceedings of the Universiti Kebangsaan Malaysia, Faculty of Science and Technology 2014 Postgraduate Colloquium

A2 - Ibrahim, Zahari

A2 - Maideen, Haja Maideen Kader

A2 - Ibrahim, Nazlina

A2 - Karim, Nurul Huda Abd

A2 - Yusof, Taufik

A2 - Razak, Fatimah Abdul

A2 - Maseran, Nurulkamal

A2 - Khalid, Rozida Mohd

A2 - Ibrahim, Noor Baa'yah

A2 - Sidek, Hasidah Mohd.

A2 - Noorani, Mohd Salmi Md

A2 - Simon, Norbert

PB - American Institute of Physics Inc.

ER -