Effects of annealing and cobalt implantation on the optical properties of βFeSi2.

1993 ◽  
Vol 316 ◽  
Author(s):  
M S Finney ◽  
Z Yang ◽  
M A Harry ◽  
K J Reeson ◽  
K P Homewood ◽  
...  
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Band Gap ◽  
Small Dose ◽  
Ion Beam ◽  
Hydrogen Plasma ◽  
High Dose ◽  
Additional Band ◽  
A Value ◽  
Fe Implantation

ABSTRACTIn this paper optical absorption and photoluminescence (PL) techniques are used to study the optical properties of βFeSi2 layers fabricated by Ion Beam Synthesis (IBS). The way in which the band-gap varies when a small dose of Co is added before Fe implantation is also investigated. Our results indicate that the band-gap for βFeSi2 is direct with a value of O.87eV. When a sufficiently high dose (1×1016cm-2) of Co is implanted prior to Fe we see the appearance of an additional band-gap after annealing at 1173K which we attribute to the formation of a ternary CoxFeySiz, phase. We also show that by placing the sample in a hydrogen plasma it is possible to raise the temperature at which PL occurs in βFeSi2 to ~ 200K.

Effects of annealing and cobalt implantation on the optical properties of βFeSi2

1993 ◽  
Vol 320 ◽  
Author(s):  
M S Finney ◽  
Z Yang ◽  
M A Harry ◽  
K J Reeson ◽  
K P Homewood ◽  
...  
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Band Gap ◽  
Small Dose ◽  
Ion Beam ◽  
Hydrogen Plasma ◽  
High Dose ◽  
Additional Band ◽  
A Value ◽  
Fe Implantation

ABSTRACTIn this paper optical absorption and photoluminescence (PL) techniques are used to study the optical properties of βFeSi2 layers fabricated by Ion Beam Synthesis (IBS). The way in which the band-gap varies when a small dose of Co is added before Fe implantation is also investigated. Our results indicate that the band-gap for βFeSi2 is direct with a value of 0.87eV. When a sufficiently high dose (1 ×10 16cm2) of Co is implanted prior to Fe we see the appearance of an additional band-gap after annealing at 1173K which we attribute to the formation of a ternary CoxFeySiz phase. We also show that by placing the sample in a hydrogen plasma it is possible to raise the temperature at which PL occurs in βFeSi2 to σ 200K.

Tuning band gap and optical properties of SnX2 nanosheets: Hybrid functional studies

2016 ◽  
Vol 30 (10) ◽  
pp. 1650120 ◽  
Author(s):  
P. Guo ◽  
Y. W. Luo ◽  
Y. Jia
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Band Gap ◽  
Electronic Structures ◽  
Threshold Values ◽  
Hybrid Functional ◽  
Functional Studies ◽  
Quantum Size ◽  
Light Activity ◽  
Optical Applications

Based on hybrid functional calculations, the electronic structures and optical properties are investigated in the monolayer and bilayer tin dichalcogenides SnX2 (X = S and Se) nanosheets. Numerical results show that quantum size effects are obvious on the electronic structures and optical absorption in the SnS2 and SnSe2 nanosheets. The band gap values increase when the nanosheets layer numbers decrease. Moreover, for SnSe2 nanosheet, the optical absorption coefficients are high and its threshold values lie in the visible light activity range. These results are interesting and indicate that SnS2 and SnSe2 nanosheets may serve as the promising candidates for visible optical applications.

QUANTUM CONFINEMENT EFFECTS ON THE OPTICAL PROPERTIES OF ION BEAM SPUTTERED NICKEL OXIDE THIN FILMS

2001 ◽  
Vol 15 (02) ◽  
pp. 191-200 ◽  
Author(s):  
M. GHANASHYAM KRISHNA ◽  
A. K. BHATTACHARYA
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Nickel Oxide ◽  
Band Gap ◽  
Quantum Confinement ◽  
Ion Beam ◽  
Confinement Effects ◽  
Oxide Thin Films ◽  
Quantum Confinement Effects ◽  
Nickel Oxide Thin Films

Quantum confinement effects on the optical properties of ion beam sputtered nickel oxide thin films are reported. Thin films with crystallite sizes in the range 9 to 14 nm have been deposited on to fused silica substrates. There is an increase in band gap, from 3.4 to 3.9 eV, and a decrease in refractive index, from 2.4 to 1.6, with decrease in crystallite size, that can be attributed to quantum confinement effects. The effective mass approximation has been used to explain the observed behaviour in band gap variation.

Electrical and Optical PROPERTIES OF Co ALLOYED ß-FeSi2 Formed by Ion Beam Synthesis

1993 ◽  
Vol 316 ◽  
Author(s):  
D. Panknin ◽  
W. Henrion ◽  
E. Wieser ◽  
M. Voelskow ◽  
W. Skorupa ◽  
...  
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Ion Beam ◽  
Cobalt Content ◽  
Band Gap Energy ◽  
Electrical And Optical Properties ◽  
Spreading Resistance ◽  
Gap Energy ◽  
Buried Layers ◽  
Resistance Decrease

ABSTRACTBy subsequent implantation of iron and cobalt into silicon buried layers of semiconducting ß-(Fe1-xCo1-x)Si2 are formed. The band gap energy as well as the spreading resistance decrease with increasing cobalt content. The microstructure of the suicide layers is characterized by XTEM images.

Electronic and optical properties of CsPb2Br5: A first-principles study

2019 ◽  
Vol 33 (22) ◽  
pp. 1950266 ◽  
Author(s):  
Mingge Jin ◽  
Zhibing Li ◽  
Feng Huang ◽  
Weiliang Wang
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Visible Light ◽  
Band Gap ◽  
First Principles ◽  
First Principles Calculations ◽  
Hybrid Functional ◽  
Electronic And Optical Properties ◽  
Optical Absorbance ◽  
Indirect Band Gap

There are conflicting understandings of the electronic and optical properties of CsPb2Br5. We investigated the electronic and optical properties of CsPb2Br5 with first-principles calculations. It is confirmed that CsPb2Br5 is a semiconductor with an indirect band gap of 3.08 eV at GGA/PBE level and 3.72 eV at the HSE06 hybrid functional level. The PBE results demonstrate that the inclusion of SOC slightly reduces the band gap. We calculate the optical absorbance/emission spectrum of CsPb2Br5. It is found the optical absorption edges locate at 360–380 nm, shorter than the wavelength of visible light. Our results support the experimental results of Li et al. [Chem. Commun. 52 (2016) 11296] and Zhang et al. [J. Mater. Chem. C 6 (2018) 446].

Novel electronic and optical properties of ultrathin silicene/arsenene heterostructures and electric field effects

2017 ◽  
Vol 19 (16) ◽  
pp. 10644-10650 ◽  
Author(s):  
Huabing Shu ◽  
Yilong Tong ◽  
Jiyuan Guo
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Electric Field ◽  
Band Gap ◽  
Absorption Spectra ◽  
Optical Absorption Spectra ◽  
Electric Field Effects ◽  
Electronic And Optical Properties ◽  
Vertical Electric Field ◽  
Variable Band Gap

The variable band-gap of the Si/As heterostructure (left) and optical absorption spectra for AA-stacking under a vertical electric field (right).

scholarly journals Influence of Air Annealing and Gamma Ray Irradiation on the Optical Properties of Cl16FePc Thin Films

2012 ◽  
Vol 9 (4) ◽  
pp. 2439-2445 ◽  
Author(s):  
Raji Koshy ◽  
C. S. Menon
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Absorption Spectrum ◽  
Optical Absorption ◽  
Band Gap ◽  
Gamma Ray ◽  
Optical Transition ◽  
High Electron ◽  
Glass Substrates ◽  
Optical Dielectric Constant

Metal phthalocyanines are one of the most promising candidates to be used in the fabrication of such devices. Among various phthalocyanines, Iron Hexadecachloro Phthalocyanine (Cl16FePc) has received less attention. Basic characteristics of Cl16FePc are not reported in literature. Hexadecacholoro phthalocyanines have attracted interest as possible n-type organic semiconductor with high electron mobility and good stability characteristics. In the present work we investigate the optical band gap of the Cl16FePc thin films from the optical absorption spectrum as a function of air annealing temperatures and their suitability for the fabrication of molecular electronic devices. Some optical properties of the samples were studied as a function of γ-radiation doses also. Optical transition is found to be of direct type and optical band gaps are determined by analyzing the absorption spectrum. Vacuum sublimed thin films of Iron hexadecachloro phthalocyanine were prepared at room temperature onto glass substrates at a base pressure of 10-5Torr on precleaned glass substrates using Hind Hivac 12A4 coating plant. The optical energy band gap Eg were calculated. The mechanism of optical absorption follow the rule of direct transition. In the present paper we also report refractive index, real and imaginary parts of optical dielectric constant etc. from the reflectance measurements.

Structural Stability and Optical Properties of hexagonal and cubic CdSe Nanocrystals synthesized in MgO

2004 ◽  
Vol 848 ◽  
Author(s):  
S.W.H. Eijt ◽  
van Huis ◽  
P.E. Mijnarends ◽  
B.J. Kooi ◽  
M. Nanu
Keyword(s):  
Optical Properties ◽  
Ion Implantation ◽  
Band Gap ◽  
Structural Changes ◽  
Optical Absorption Spectroscopy ◽  
Cdse Nanocrystals ◽  
High Dose ◽  
Electronic Band ◽  
Supersaturated Solid Solutions ◽  
Direct Band

ABSTRACTWe present a study of CdSe nanocrystals synthesized in MgO by precipitation of Cd and Se supersaturated solid solutions, created in MgO single crystals by ion implantation, in the temperature range between 300 °C and 1100 °C. For high-dose ion implantation, optical absorption spectroscopy revealed the presence of the ∼1.8 eV CdSe semiconductor band-edge. Small sized nanocrystals adopt the rocksalt instead of the wurtzite structure because the former fits better in the MgO matrix and results in lower interface energies. A better understanding of these structural changes and optical properties is obtained from ab-initio total energy calculations on wurtzite, zincblende and rocksalt CdSe using the VASP pseudopotential code. The calculated electronic band structures are compared of zincblende CdSe, a direct band-gap semiconductor, and rocksalt CdSe, which has an indirect optical band-gap.

Modulation of the band structures and optical properties of holey C2N nanosheets by alloying with group IV and V elements

2016 ◽  
Vol 4 (39) ◽  
pp. 9294-9302 ◽  
Author(s):  
Juan Du ◽  
Congxin Xia ◽  
Tianxing Wang ◽  
Wenqi Xiong ◽  
Jingbo Li
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Band Gap ◽  
Group Iv ◽  
Band Structures ◽  
Alloy Concentration

The band gap and optical absorption can be tuned effectively by the alloy concentration x in the C2N1−xPx and C2N1−xAsx alloys.

Optical Properties Of Si Nanocrystals Formed In Si02 By Ion Implantation

1998 ◽  
Vol 507 ◽  
Author(s):  
C. W. White ◽  
S. P. Withrow ◽  
A. Meldrum ◽  
J. D. Budai ◽  
D. M. Hembree ◽  
...  
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Ion Implantation ◽  
Quantum Confinement ◽  
Dose Dependence ◽  
Interface States ◽  
High Dose ◽  
Size Dependent ◽  
Si Nanocrystals

ABSTRACTSi nanocrystals formed in SiO2 by high-dose ion implantation and annealing give rise to strong optical absorption and intense photoluminescence (PL). The dose dependence of optical absorption provides evidence for size-dependent quantum confinement in the Si nanocrystals. PL peak energies are nearly independent of dose suggesting that surface or interface states play an important role in PL. Estimates of absorption bandgaps in the nanocrystals are given.

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