scholarly journals Abrupt Change Effect of Bandgap Energy on Quantum System of Silicon Nanowire

Crystals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 340 ◽  
Author(s):  
Zhong-Mei Huang ◽  
Shi-Rong Liu ◽  
Hong-Yan Peng ◽  
Xin Li ◽  
Wei-Qi Huang
Keyword(s):  
Quantum System ◽  
Quantum Confinement ◽  
Abrupt Change ◽  
Silicon Nanowire ◽  
Laser Deposition ◽  
Bandgap Energy ◽  
Main Role ◽  
Simulating Calculation ◽  
Change Effect ◽  
Radius Size

In the quantum system of Si nanowire (NW), the energy bandgap obviously increases with decreasing radius size of NW, in which the quantum confinement (QC) effect plays a main role. Furthermore, the simulation result demonstrated that the direct bandgap can be obtained as the NW diameter is smaller than 3 nm in Si NW with (001) direction. However, it is discovered in the simulating calculation that the QC effect disappears as the NW diameter arrives at size of monoatomic line, in which its bandgap sharply deceases where the abrupt change effect in bandgap energy occurs near the idea quantum wire. In the experiment, we fabricated the Si NW structure by using annealing and pulsed laser deposition methods, in which a novel way was used to control the radius size of Si NW by confining cylinder space of NW in nanolayer. It should have a good application on optic-electronic waveguide of silicon chip.

Abrupt Change of Bandgap Energy in Quantum System of Nanolayer on Silicon Surface

2020 ◽  
Author(s):  
Wei-Qi Huang ◽  
Shi-Rong Liu ◽  
Zi-Lin Wang ◽  
Cui-Fen Chen ◽  
Ke Wang ◽  
...  
Keyword(s):  
Electron Beam ◽  
Quantum System ◽  
Electron Beam Irradiation ◽  
Abrupt Change ◽  
Irradiation Time ◽  
Bandgap Energy ◽  
Main Role ◽  
Simulating Calculation ◽  
Change Effect ◽  
Simulated Calculation

Abstract In the quantum system of nanolayer (NL) on silicon, the bandgap energy obviously increases with decreasing thickness of NL, in which the quantum confinement (QC) effect plays a main role. In simulating calculation, the QC effect has been exhibited as the thickness of Si NL changes along with (100), (110) and (111) direction respectively. And the simulation result demonstrated that the direct bandgap can be obtained as the NL with (001) direction is thinner than 10nm on Si surface. However, it is discovered in the simulated calculation that the QC effect disappears as the NL thickness arrives at size of monoatomic layer, in which its bandgap sharply deceases, where the abrupt change effect in bandgap energy occurs near idea 2D-layer. In experiment, we fabricated the Si NL structure by using electron beam irradiation and pulsed laser deposition methods, in which a novel way was used to control the NL thickness by modulating irradiation time of electron beam. The new effect should have a good application on optic-electronic chip of silicon.

Change of Bandgap Energy in Quantum System of Nanolayer on Silicon

NANO ◽  
2021 ◽  
pp. 2150112
Author(s):  
Wei-Qi Huang ◽  
Zi-Lin Wang ◽  
Cui-Fen Chen ◽  
Ke Wang ◽  
Hong-Yan Peng ◽  
...  
Keyword(s):  
Electron Beam ◽  
Quantum System ◽  
Quantum Confinement ◽  
Electron Beam Irradiation ◽  
Abrupt Change ◽  
Irradiation Time ◽  
Bandgap Energy ◽  
Main Role ◽  
Change Effect ◽  
Simulated Calculation

In the quantum system of nanolayer (NL) on silicon, the bandgap energy obviously increases with the decrease of NL thickness, where the quantum confinement (QC) effect plays the main role as the thickness of Si NL changes along with (100), (110) and (111) directions, respectively. And the simulation result demonstrated that the direct bandgap can be obtained as the NL with (001) direction is thinner than 10 nm on Si surface. However, it is discovered in the simulated calculation that the QC effect disappears as the NL thickness arrives at the size of the monoatomic layer, in which its bandgap sharply decreases, where the abrupt change effect in bandgap energy occurs near-ideal 2D-layer. In the experiment, we fabricated the Si NL structure by using electron beam irradiation and laser deposition methods, in which a novel way was used to control the NL thickness by modulating irradiation time of the electron beam. The new effect should have a good application on a photonic-electronic chip of silicon.

Size Effect in Germanium Nanostructures Fabricated by Pulsed Laser Deposition

1999 ◽  
Vol 581 ◽  
Author(s):  
K.M. Hassan ◽  
A.K. Sharma ◽  
J. Narayan ◽  
J.F. Muth ◽  
C.W. Teng ◽  
...  
Keyword(s):  
Pulsed Laser Deposition ◽  
Band Gap ◽  
Quantum Confinement ◽  
Three Dimensional ◽  
Pulsed Laser ◽  
Wide Band ◽  
Laser Deposition ◽  
Island Growth ◽  
Wide Band Gap ◽  
Average Size

ABSTRACTWe have fabricated Ge nanostructures buried in AlN and Al2O3 matrices grown on Si(111) and sapphire substrates by pulsed laser deposition. Our approach involved three-dimensional island growth of low band-gap material followed by a layer of wide band-gap material. The nanodots were uniformly distributed in between alternating layers of AlN or Al2O3. It was observed that these nanodots exhibit crystalline structure when grown at 300-500 °C. The average size of Ge islands was determined to be ∼5-15 nm, which could be varied by controlling laser deposition and substrate parameters. The Raman spectrum showed a peak of the Ge-Ge vibrational mode downward shifted upto 295 cm− which is caused by quantum confinement of phonons in the Ge-dots. The photoluminescence of the Ge dots (size ∼15nm) was blue shifted by ∼0.266 eV from the bulk Ge value of 0.73 eV at 77 K, resulting in a distinct peak at ∼1.0 eV. The spectral positions of both E1 and E2 transitions in the absorption spectra at room temperature and 77K shift toward higher energy as the Ge dot size decreases. The interpretation of these behaviors in terms of quantum confinement is discussed in this work, and the importance of pulsed laser deposition in fabricating novel nanostructures is emphasized

Quantum Confinement of GaAs Nanocrystals Deposited on PMMA Microspheres Using Pulsed Laser Ablation

2013 ◽  
Vol 660 ◽  
pp. 3-9
Author(s):  
Jeong Ho Ryu ◽  
Soon Yong Kweon ◽  
Jung Il Lee ◽  
Sung Lim Ryu
Keyword(s):  
Laser Ablation ◽  
Pulsed Laser Deposition ◽  
Quantum Confinement ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Average Diameter ◽  
Laser Deposition ◽  
Spherical Particles ◽  
Novel Approach

A modified pulsed laser deposition (PLD) was employed to deposit GaAs nanocrystals on the surface of PMMA microspheres. This novel approach is distinguished by the fact that laser ablated materials are deposited uniformly onto the surface of spherical particles that are held constantly in a particle fludization unit. The XRD, SEM, EDX, TEM, EDP and PL results confirmed that cubic structured GaAs nanocrystals were deposited uniformly on the surface of PMMA microspheres with an average diameter of about 15 nm.

Synthesize of SrxLa1-xTiO3 Visible Light Responces Photocatalyst Films for the Water-Splitting Reaction by Pulsed Laser Deposition

2013 ◽  
Vol 481 ◽  
pp. 125-128
Author(s):  
Satoshi Kurumi ◽  
Masateru Saito ◽  
Takayuki Kurihara ◽  
Kaoru Suzuki
Keyword(s):  
Visible Light ◽  
Pulsed Laser Deposition ◽  
Water Splitting ◽  
Pulsed Laser ◽  
White Paper ◽  
Laser Deposition ◽  
Bandgap Energy ◽  
Gas Generation ◽  
Light Responses ◽  
Photocatalytic Films

This In this study, we report on the growth techniques of SrxLa1-xTiO3 visible-light responses photocatalytic films by pulsed laser deposition for the H2 gas generation system as the fuel cell devices. XRD profile showed SrTiO3 peaks were obtained at the all films. Bandgap energy of films were decreaed with increasing the La ratio from 3.2 eV to 2.9 eV. Water splitting reaction were observed at the all films, and the maximum value of the gas generation was 7.3 μmol/cm2h at x = 0.7 film.document explains and demonstrates how to prepare your camera-ready manuscript for Trans Tech Publications. The best is to read these instructions and follow the outline of this text. The text area for your manuscript must be 17 cm wide and 25 cm high (6.7 and 9.8 inches, resp.). Do not place any text outside this area. Use good quality, white paper of approximately 21 x 29 cm or 8 x 11 inches (please do not change the document setting from A4 to letter). Your manuscript will be reduced by approximately 20% by the publisher. Please keep this in mind when designing your figures and tables etc.

Quantum confinement effect in ZnO thin films grown by pulsed laser deposition

2008 ◽  
Vol 93 (17) ◽  
pp. 173104 ◽  
Author(s):  
J. C. Nie ◽  
J. Y. Yang ◽  
Y. Piao ◽  
H. Li ◽  
Y. Sun ◽  
...  
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Quantum Confinement ◽  
Quantum Confinement Effect ◽  
Pulsed Laser ◽  
Confinement Effect ◽  
Laser Deposition ◽  
Zno Thin Films

Quantum Confinement Effects in Capacitance Behavior of Multigate Silicon Nanowire MOSFETs

2011 ◽  
Vol 10 (2) ◽  
pp. 300-309 ◽  
Author(s):  
Aryan Afzalian ◽  
Chi-Woo Lee ◽  
Nima Dehdashti Akhavan ◽  
Ran Yan ◽  
Isabelle Ferain ◽  
...  
Keyword(s):  
Quantum Confinement ◽  
Silicon Nanowire ◽  
Confinement Effects ◽  
Quantum Confinement Effects ◽  
Nanowire Mosfets

TIGHT-BINDING METHOD FOR QUANTUM-CONFINEMENT ENERGY CALCULATIONS IN THE CdSe/ZnSe MULTIPLE QUANTUM WELLS

2008 ◽  
Vol 19 (11) ◽  
pp. 1635-1645
Author(s):  
NACIR TIT ◽  
IHAB M. OBAIDAT
Keyword(s):  
Quantum Wells ◽  
Quantum Confinement ◽  
Bound States ◽  
Energy Levels ◽  
Tight Binding ◽  
Relevant Information ◽  
Physical Models ◽  
Multiple Quantum Wells ◽  
Bandgap Energy ◽  
Multiple Quantum

We present an efficient method to calculate the quantum-confinement energy of charge carriers in the ( ZnSe )M( CdSe )N (001) multiple quantum wells (MQW). The method is based on the 3D empirical sp3s* tight-binding models, which include the spin-orbit coupling. The method can handle large systems while it takes account of the band mixing caused by the strain and confinement. In these perspectives, it proves itself more reliable than the traditional effective-mass approach (EMA) by further generating more relevant information about the quantum states localized within the wells; in particular, the number of bound states and their energy levels and their corresponding wavefunctions were obtained based on more realistic physical models. The quantum-confinement energy, bandgap energy, and band structures are studied versus the CdSe well width (N). The results are found to be comparable with those experimentally obtained using photoluminescence.

Low Temperature Synthesis of Colloidal CdSe Quantum Dots

2007 ◽  
Vol 7 (11) ◽  
pp. 3780-3783 ◽  
Author(s):  
Seongmi Hwang ◽  
Youngmin Choi ◽  
Beyong-Hwan Ryu
Keyword(s):  
Quantum Confinement ◽  
Growth Time ◽  
Cdse Nanocrystals ◽  
Bandgap Energy ◽  
Synthetic Method ◽  
Cdse Quantum Dots ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis ◽  
Transmission Electron ◽  
Octyl Amine

In this study, the CdSe nanocrystals were prepared in phenyl ether and octyl amine to investigate the variations of their size, bandgap energy, and photoluminescence with growth time and temperature. The sizes of the CdSe nanocrystals were measured using High Resolution Transmission Electron Microscopy (HRTEM), and found to be nearly monodisperse for relatively low growth temperature, 130 °C. Their optic properties were characterized by photoluminescence measurements, which showed that the colors of the nanocrystals could be controlled. The bandgap energies of the nanocrystals were calculated theoretically and found to be in accord with quantum confinement theory. This synthetic method requires only a cheap solvent and offers good reproducibility at a lower price.

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