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.

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.

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.

Surface Modification of Cobalt Chrome Molybdenum Cast Alloy by Electron Beam Irradiation

2012 ◽  
Vol 706-709 ◽  
pp. 1973-1978
Author(s):  
Takekazu Nagae ◽  
Shigeki Kakiuchi ◽  
Hideki Yamagishi ◽  
Emi Yamaguchi ◽  
Takashi Yoneda ◽  
...  
Keyword(s):  
Electron Beam ◽  
Electron Beam Irradiation ◽  
Cast Alloy ◽  
Irradiation Time ◽  
Surface Hardness ◽  
Scanning Speed ◽  
Beam Irradiation ◽  
Alloy Plate ◽  
High Current Electron Beam ◽  
Current Electron

We irradiated the surface of a Co-Cr-Mo cast alloy plate with an electron beam in order to increase the surface hardness. An accelerating voltage of 40 kV and a current of 1~10 mA of the irradiated electron beam were used. The irradiation time for a single dot was 0.1 ms and the distance between dots (dot pitch) was 0.2 mm, corresponding to a scanning speed of 200 mm/s. A fine cellular structure was obtained by irradiating a low current electron beam. When a high current electron beam (more than 8 mA) was used for the irradiation, fine granular carbides were synthesized. The Vickers hardness of the base metal of 410 HV was increased to about 480~530 HV by the electron beam irradiation.

scholarly journals Experimental Study and Mathematical Modeling of the Processes Occurring in ZrN Coating/Silumin Substrate Systems under Pulsed Electron Beam Irradiation

Coatings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1461
Author(s):  
Nikolay N. Koval ◽  
Tamara V. Koval ◽  
Olga V. Krysina ◽  
Yurii F. Ivanov ◽  
Anton D. Teresov ◽  
...  
Keyword(s):  
Electron Beam ◽  
Surface Temperature ◽  
Electron Beam Irradiation ◽  
Irradiation Time ◽  
Subsequent Treatment ◽  
Beam Irradiation ◽  
Fast Heating ◽  
Pulsed Electron Beam ◽  
Rise Rate ◽  
Intense Electron Beam

This paper presents a study of a combined modification of silumin, which included deposition of a ZrN coating on a silumin substrate and subsequent treatment of the coating/substrate system with a submillisecond pulsed electron beam. The local temperature on the samples in the electron-beam-affected zone and the thickness of the melt zone were measured experimentally and calculated using a theoretical model. The Stefan problem was solved numerically for the fast heating of bare and ZrN-coated silumin under intense electron beam irradiation. Time variations of the temperature field, the position of the crystallization front, and the speed of the front movement have been calculated. It was found that when the coating thickness was increased from 0.5 to 2 μm, the surface temperature of the samples increased from 760 to 1070 °C, the rise rate of the surface temperature increased from 6 × 107 to 9 × 107 K/s, and the melt depth was no more than 57 μm. The speed of the melt front during the pulse was 3 × 105 µm/s. Good agreement was observed between the experimental and theoretical values of the temperature characteristics and melt zone thickness.

Electron beam irradiation of fluorinated graphene

2017 ◽  
Vol 31 (32) ◽  
pp. 1750252
Author(s):  
Lei Guo ◽  
Shengzhu Cao ◽  
Lanxi Wang
Keyword(s):  
Electron Beam ◽  
Photoelectron Spectroscopy ◽  
Electron Beam Irradiation ◽  
Irradiation Time ◽  
Electrical Characterization ◽  
Electrical Performance ◽  
Beam Irradiation ◽  
X Ray ◽  
Detection Techniques ◽  
Fluorinated Graphene

Fluorinated graphene was irradiated by electron beam, and the changing of fluorinated graphene after electron beam irradiation was found by several detection techniques of Raman, electrical characterization and X-ray photoelectron spectroscopy (XPS). Raman spectra and electric characterization confirmed that the crystal structure and electrical performance of graphene was recovered partially after electron beam irradiation. XPS results indicated that the concentration of fluorine quickly dropped from 35% to 15% just after 30 min irradiation, and then dropped, slowly to 10% with the irradiation time to 150 min. The results indicate that stimulate fluorine desorption from fluorinated graphene used electron beam completely is difficult, which means a big challenge for ESD to fabricate all graphene electronics.

Second-Harmonic Generation of the Chalcogenide Amorphous Film by Electron Beam Irradiation

2011 ◽  
Vol 415-417 ◽  
pp. 1376-1381
Author(s):  
Jun Hu ◽  
Shao Xuan Gu
Keyword(s):  
Electron Beam ◽  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Electron Beam Irradiation ◽  
Second Harmonic ◽  
Irradiation Time ◽  
Amorphous Film ◽  
Incident Electron Energy ◽  
Electric Dipoles ◽  
Electric Field Generation

PLD(pulsed laser deposition) method was used to prepare amorphous GeS2-Ga2S3-CdS chalcogenide film. Obvious SHG(second harmonic generation) was observed in electron beam irradiated film by Maker fringe method. According to Raman spectra, we discussed the mechanism of SHG and ascribed the origination of SHG to the local electric field generation under electron beam and uneven charge distribution. With the increase of accelerating voltage and the extension of irradiation time, the SHG intensity increased and reached the maximum, which is due to the enhancement of breakage of glassy isotropy with gradually increased incident electron energy and the finite population of electric dipoles leading to the saturation of SH intensity.

Methods to Monitor and Improve the Performance of Specimen Holders for Transmission Electron Cryomicroscopy

1996 ◽  
Vol 54 ◽  
pp. 454-455
Author(s):  
B. L. Armbruster ◽  
B. Kraus ◽  
M. Pan
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Electron Beam Irradiation ◽  
Beam Irradiation ◽  
Quality Of Data ◽  
Electron Cryomicroscopy ◽  
Thermal Equilibration ◽  
Transmission Electron ◽  
Electron Microscopes

One goal in electron microscopy of biological specimens is to improve the quality of data to equal the resolution capabilities of modem transmission electron microscopes. Radiation damage and beam- induced movement caused by charging of the sample, low image contrast at high resolution, and sensitivity to external vibration and drift in side entry specimen holders limit the effective resolution one can achieve. Several methods have been developed to address these limitations: cryomethods are widely employed to preserve and stabilize specimens against some of the adverse effects of the vacuum and electron beam irradiation, spot-scan imaging reduces charging and associated beam-induced movement, and energy-filtered imaging removes the “fog” caused by inelastic scattering of electrons which is particularly pronounced in thick specimens.Although most cryoholders can easily achieve a 3.4Å resolution specification, information perpendicular to the goniometer axis may be degraded due to vibration. Absolute drift after mechanical and thermal equilibration as well as drift after movement of a holder may cause loss of resolution in any direction.

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