Isotope composition dependence of the band-gap energy in diamond

2013 ◽  
Vol 88 (20) ◽  
Author(s):  
H. Watanabe ◽  
T. Koretsune ◽  
S. Nakashima ◽  
S. Saito ◽  
S. Shikata
Keyword(s):  
Band Gap ◽  
Composition Dependence ◽  
Isotope Composition ◽  
Band Gap Energy ◽  
Gap Energy

Spectroscopic Ellipsometry Analysis of InGaN/GaN and AlGaN/GaN Heterostructures Using a Parametric Dielectric Function Model

1999 ◽  
Vol 595 ◽  
Author(s):  
J. Wagner ◽  
A. Ramakrishnan ◽  
H. Obloh ◽  
M. Kunzer ◽  
K. Köhler ◽  
...  
Keyword(s):  
Band Gap ◽  
Dielectric Function ◽  
Spectroscopic Ellipsometry ◽  
Composition Dependence ◽  
Band Gap Energy ◽  
Function Model ◽  
Gap Energy ◽  
The Individual ◽  
Gap Data

AbstractSpectroscopic ellipsometry (SE) has been used for the characterization of AlGaN/GaN and InGaN/GaN heterostructures. The resulting pseudodielectric function spectra were analyzed using a multilayer approach, describing the dielectric functions of the individual layers by a parametric oscillator model. From this analysis, the dielectric function spectra of GaN, AlxGa1−xN (x≤0.16), and In0.13Ga0.87N were deduced. Further, the dependence of the AlxGa1−xN band gap energy on the Al mole fraction was derived and compared with photoluminescence data recorded on the same material. The SE band gap data are compatible with a bowing parameter close to 1 eV for the composition dependence of the AlxGa1−xN gap energy. Finally, the parametric dielectric functions have been used to model the pseudodielectric function spectrum of a complete GaN/AlGaN/InGaN LED structure.

Composition dependence of the band gap energy for the dilute nitride and As-rich GaNxSbyAs1−x−y (0≤x≤0.05, 0≤y≤0.3)

2016 ◽  
Vol 485 ◽  
pp. 35-38 ◽  
Author(s):  
Chuan-Zhen Zhao ◽  
Heng-Fei Guo ◽  
Tong Wei ◽  
Sha-Sha Wang ◽  
Ke-Qing Lu
Keyword(s):  
Band Gap ◽  
Composition Dependence ◽  
Band Gap Energy ◽  
Dilute Nitride ◽  
Gap Energy

scholarly journals Composition Dependence of the Band Gap Energy of InxGa1−xN Layers on GaN (x≤0.15) Grown by Metal-Organic Chemical Vapor Deposition

1999 ◽  
Vol 4 (S1) ◽  
pp. 106-111 ◽  
Author(s):  
J. Wagner ◽  
A. Ramakrishnan ◽  
D. Behr ◽  
M. Maier ◽  
N. Herres ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Band Gap ◽  
Vapor Deposition ◽  
Composition Dependence ◽  
Chemical Vapor ◽  
Band Gap Energy ◽  
Organic Chemical ◽  
Gap Energy ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

We report on the composition dependence of the band gap energy of strained hexagonal InxGa1−xN layers on GaN with x≤0.15, grown by metal-organic chemical vapor deposition on sapphire substrates. The composition of the (InGa)N was determined by secondary ion mass spectroscopy. High-resolution X-ray diffraction measurements confirmed that the (InGa)N layers with typical thicknesses of 30 nm are pseudomorphically strained to the in-plane lattice parameter of the underlying GaN. Room-temperature photoreflection spectroscopy and spectroscopic ellipsometry were used to determine the (InGa)N band gap energy. The composition dependence of the band gap energy of the strained (InGa)N layers was found to be given by EG(x)=3.43−3.28 × (eV) for x≤0.15. When correcting for the strain induced shift of the fundamental energy gap, a bowing parameter of 3.2 eV was obtained for the composition dependence of the gap energy of unstrained (InGa)N.

scholarly journals Spectroscopic Ellipsometry Analysis of InGaN/GaN and AlGaN/GaN Heterostructures Using a Parametric Dielectric Function Model

2000 ◽  
Vol 5 (S1) ◽  
pp. 775-781
Author(s):  
J. Wagner ◽  
A. Ramakrishnan ◽  
H. Obloh ◽  
M. Kunzer ◽  
K. Köhler ◽  
...  
Keyword(s):  
Band Gap ◽  
Dielectric Function ◽  
Spectroscopic Ellipsometry ◽  
Composition Dependence ◽  
Band Gap Energy ◽  
Function Model ◽  
Gap Energy ◽  
The Individual ◽  
Gap Data

Spectroscopic ellipsometry (SE) has been used for the characterization of AlGaN/GaN and InGaN/GaN heterostructures. The resulting pseudodielectric function spectra were analyzed using a multilayer approach, describing the dielectric functions of the individual layers by a parametric oscillator model. From this analysis, the dielectric function spectra of GaN, AlxGa1−xN (x≤0.16), and In0.13Ga0.87N were deduced. Further, the dependence of the AlxGa1−xN band gap energy on the Al mole fraction was derived and compared with photoluminescence data recorded on the same material. The SE band gap data are compatible with a bowing parameter close to 1 eV for the composition dependence of the AlxGa1−xN gap energy. Finally, the parametric dielectric functions have been used to model the pseudodielectric function spectrum of a complete GaN/AlGaN/InGaN LED structure.

The Composition Dependence of the Band Gap Energy for the O-Rich ZnSexO1−x

2018 ◽  
Vol 47 (7) ◽  
pp. 3897-3901 ◽  
Author(s):  
Chuan-Zhen Zhao ◽  
Tong Wei ◽  
Xiao-Dong Sun ◽  
Sha-Sha Wang ◽  
Jun Wang
Keyword(s):  
Band Gap ◽  
Composition Dependence ◽  
Band Gap Energy ◽  
Gap Energy

Composition Dependence of the Band Gap Energy of InxGal-xN Layers on GaN (x≤0.15) Grown by Metal-Organic Chemical Vapor Deposition

1998 ◽  
Vol 537 ◽  
Author(s):  
J. Wagner ◽  
A. Ramakrishnan ◽  
D. Behr ◽  
M. Maier ◽  
N. Herres ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Band Gap ◽  
Vapor Deposition ◽  
Composition Dependence ◽  
Chemical Vapor ◽  
Band Gap Energy ◽  
Organic Chemical ◽  
Gap Energy ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

AbstractWe report on the composition dependence of the band gap energy of strained hexagonal InGal-,N layers on GaN with x≤0.15, grown by metal-organic chemical vapor deposition on sapphire substrates. The composition of the (InGa)N was determined by secondary ion mass spectroscopy. High-resolution X-ray diffraction measurements confirmed that the (InGa)N layers with typical thicknesses of 30 nm are pseudomorphically strained to the in-plane lattice parameter of the underlying GaN. Room-temperature photoreflection spectroscopy and spectroscopic ellipsometry were used to determine the (InGa)N band gap energy. The composition dependence of the band gap energy of the strained (InGa)N layers was found to be given by EG(x)=3.43-3.28.x (eV) for x≤0.15. When correcting for the strain induced shift of the fundamental energy gap, a bowing parameter of 3.2 eV was obtained for the composition dependence of the gap energy of unstrained (InGa)N.

Modification of optical properties of PC-PBT/Cr2O3 and PC-PBT/CdS nanocomposites by gamma irradiation

2020 ◽  
Vol 92 (2) ◽  
pp. 20402
Author(s):  
Kaoutar Benthami ◽  
Mai ME. Barakat ◽  
Samir A. Nouh
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Band Gap ◽  
Color Difference ◽  
Band Gap Energy ◽  
Polybutylene Terephthalate ◽  
Γ Irradiation ◽  
Gap Energy ◽  
Vis Spectroscopy ◽  
Oxygen Atoms

Nanocomposite (NCP) films of polycarbonate-polybutylene terephthalate (PC-PBT) blend as a host material to Cr2O3 and CdS nanoparticles (NPs) were fabricated by both thermolysis and casting techniques. Samples from the PC-PBT/Cr2O3 and PC-PBT/CdS NCPs were irradiated using different doses (20–110 kGy) of γ radiation. The induced modifications in the optical properties of the γ irradiated NCPs have been studied as a function of γ dose using UV Vis spectroscopy and CIE color difference method. Optical dielectric loss and Tauc's model were used to estimate the optical band gaps of the NCP films and to identify the types of electronic transition. The value of optical band gap energy of PC-PBT/Cr2O3 NCP was reduced from 3.23 to 3.06 upon γ irradiation up to 110 kGy, while it decreased from 4.26 to 4.14 eV for PC-PBT/CdS NCP, indicating the growth of disordered phase in both NCPs. This was accompanied by a rise in the refractive index for both the PC-PBT/Cr2O3 and PC-PBT/CdS NCP films, leading to an enhancement in their isotropic nature. The Cr2O3 NPs were found to be more effective in changing the band gap energy and refractive index due to the presence of excess oxygen atoms that help with the oxygen atoms of the carbonyl group in increasing the chance of covalent bonds formation between the NPs and the PC-PBT blend. Moreover, the color intensity, ΔE has been computed; results show that both the two synthesized NCPs have a response to color alteration by γ irradiation, but the PC-PBT/Cr2O3 has a more response since the values of ΔE achieved a significant color difference >5 which is an acceptable match in commercial reproduction on printing presses. According to the resulting enhancement in the optical characteristics of the developed NCPs, they can be a suitable candidate as activate materials in optoelectronic devices, or shielding sheets for solar cells.

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