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

2014 ◽  
Author(s):  
M. M. Anas ◽  
A. P. Othman ◽  
G. Gopir
Keyword(s):  
Density Functional Theory ◽  
Quantum Dots ◽  
Quantum Confinement ◽  
Density Functional ◽  
Quantum Confinement Effect ◽  
Confinement Effect ◽  
First Principle ◽  
Silicon Quantum Dots ◽  
Functional Theory

Density Functional Theory Study on Energy Band Gap of Armchair Silicene Nanoribbons with Periodic Nanoholes

MRS Advances ◽  
2016 ◽  
Vol 1 (22) ◽  
pp. 1613-1618 ◽  
Author(s):  
Sadegh Mehdi Aghaei ◽  
Irene Calizo
Keyword(s):  
Density Functional Theory ◽  
Band Gap ◽  
Energy Band ◽  
Quantum Confinement ◽  
Density Functional ◽  
Quantum Confinement Effect ◽  
Density Functional Theory Study ◽  
Energy Band Gap ◽  
Functional Theory ◽  
Silicene Nanoribbons

ABSTRACTIn this study, density functional theory (DFT) is employed to investigate the electronic properties of armchair silicene nanoribbons perforated with periodic nanoholes (ASiNRPNHs). The dangling bonds of armchair silicene nanoribbons (ASiNR) are passivated by mono- (:H) or di-hydrogen (:2H) atoms. Our results show that the ASiNRs can be categorized into three groups based on their width: W = 3P − 1, 3P, and 3P + 1, P is an integer. The band gap value order changes from “EG (3P − 1) < EG (3P) < EG (3P + 1)” to “EG (3P + 1) < EG (3P − 1) < EG (3P)” when edge hydrogenation varies from mono- to di-hydrogenated. The energy band gap values for ASiNRPNHs depend on the nanoribbons width and the repeat periodicity of the nanoholes. The band gap value of ASiNRPNHs is larger than that of pristine ASiNRs when repeat periodicity is even, while it is smaller than that of pristine ASiNRs when repeat periodicity is odd. In general, the value of energy band gap for ASiNRPNHs:2H is larger than that of ASiNRPNHs:H. So a band gap as large as 0.92 eV is achievable with ASiNRPNHs of width 12 and repeat periodicity of 2. Furthermore, creating periodic nanoholes near the edge of the nanoribbons cause a larger band gap due to a strong quantum confinement effect.

Quantum Confinement in CdTe Quantum Dots: Investigation through Cyclic Voltammetry Supported by Density Functional Theory (DFT)

2011 ◽  
Vol 115 (14) ◽  
pp. 6243-6249 ◽  
Author(s):  
Santosh K. Haram ◽  
Anjali Kshirsagar ◽  
Yogini D. Gujarathi ◽  
Pravin P. Ingole ◽  
Omkar A. Nene ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Quantum Dots ◽  
Cyclic Voltammetry ◽  
Quantum Confinement ◽  
Density Functional ◽  
Cdte Quantum Dots ◽  
Functional Theory

scholarly journals Electronic and Optical Properties of Small Hydrogenated Silicon Quantum Dots Using Time-Dependent Density Functional Theory

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Muhammad Mus-’ab Anas ◽  
Geri Gopir
Keyword(s):  
Density Functional Theory ◽  
Quantum Dots ◽  
Absorption Spectrum ◽  
Density Functional ◽  
Time Dependent ◽  
Silicon Quantum Dots ◽  
Functional Theory ◽  
Hydrogenated Silicon ◽  
Small Quantum ◽  
Dependent Density

This paper presents a systematic study of the absorption spectrum of various sizes of small hydrogenated silicon quantum dots of quasi-spherical symmetry using the time-dependent density functional theory (TDDFT). In this study, real-time and real-space implementation of TDDFT involving full propagation of the time-dependent Kohn-Sham equations were used. The experimental results for SiH4and Si5H12showed good agreement with other earlier calculations and experimental data. Then these calculations were extended to study larger hydrogenated silicon quantum dots with diameter up to 1.6 nm. It was found that, for small quantum dots, the absorption spectrum is atomic-like while, for relatively larger (1.6 nm) structure, it shows bulk-like behavior with continuous plateau with noticeable peak. This paper also studied the absorption coefficient of silicon quantum dots as a function of their size. Precisely, the dependence of dot size on the absorption threshold is elucidated. It was found that the silicon quantum dots exhibit direct transition of electron from HOMO to LUMO states; hence this theoretical contribution can be very valuable in discerning the microscopic processes for the future realization of optoelectronic devices.

First-principle investigations on structural, elastic, electronic and thermodynamic properties of ScX3(X = Ir,Pd,Pt and Rh) under high pressure

2015 ◽  
Vol 29 (32) ◽  
pp. 1550201 ◽  
Author(s):  
Bao Chen ◽  
Santao Qi ◽  
Hongquan Song ◽  
Chuanhui Zhang ◽  
Jiang Shen
Keyword(s):  
Density Functional Theory ◽  
Thermodynamic Properties ◽  
Bulk Modulus ◽  
Density Functional ◽  
External Pressure ◽  
First Principle ◽  
Zero Temperature ◽  
Functional Theory ◽  
Change Trend ◽  
Experimental Values

In this paper, the structural, elastic, electronic and thermodynamic properties of [Formula: see text] and [Formula: see text] intermetallic compound are investigated using pseudopotential method based on density functional theory (DFT) under pressure. In this work, the calculated lattice constant and bulk modulus are in accordance with experimental values at zero temperature and zero pressure. The bulk modulus [Formula: see text], shear modulus [Formula: see text] and Young’s modulus [Formula: see text] for [Formula: see text] and [Formula: see text] increase with the increasing external pressure. It is noted that [Formula: see text] of investigated compound has the largest [Formula: see text], [Formula: see text] and [Formula: see text]. The results of [Formula: see text] and [Formula: see text] have the same change trend, but [Formula: see text] presents an irregular change for [Formula: see text] and [Formula: see text]. The density of states for [Formula: see text] and [Formula: see text] are investigated at 0, 30 and 50 GPa. In addition, the thermodynamic properties as a function of temperature at different pressure are also studied.

scholarly journals Electronic Structure and Optical Properties of Co and Fe Doped ZnO

2016 ◽  
Vol 43 ◽  
pp. 23-28 ◽  
Author(s):  
Chun Ping Li ◽  
Ge Gao ◽  
Xin Chen
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Electronic Structures ◽  
Density Functional ◽  
Band Gaps ◽  
First Principle ◽  
Functional Theory ◽  
Doped Zno ◽  
Pseudo Potential ◽  
Co Doped

First-principle ultrasoft pseudo potential approach of the plane wave based on density functional theory (DFT) has been used for studying the electronic characterization and optical properties of ZnO and Fe, Co doped ZnO. The results show that the doping impurities change the lattice parameters a little, but bring more changes in the electronic structures. The band gaps are broadened by doping, and the Fermi level accesses to the conduction band which will lead the system to show the character of metallic properties. The dielectric function and absorption peaks are identified and the changes compared to pure ZnO are analyzed in detail.

Sign in / Sign up

Export Citation Format

Share Document