Reduction of the Optical Absorption of Zinc Germanium Phosphide Via Post-Growth Thermal Anneal

1999 ◽  
Vol 607 ◽  
Author(s):  
How-Ghee Ang ◽  
Leng-Leng Chng ◽  
Yiew-Wang Lee ◽  
Colin J. Flynn ◽  
Phil C. Smith ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Absorption Coefficient ◽  
Thermal Annealing ◽  
Annealing Time ◽  
Near Infrared ◽  
Annealing Temperature ◽  
Near Band Edge ◽  
Percentage Decrease ◽  
Optimal Annealing Temperature ◽  
Zinc Germanium Phosphide

AbstractThis paper describes the reduction of the near-band-edge absorption of zinc germanium phosphide (ZGP) through thermal annealing. The effects of the annealing time, temperature and vapour atmosphere on the reduction of the optical absorption in the near infrared (NIR) region are reported. Results have shown that the optical absorption at 2µm is reduced by at least 50% upon thermal anneal of ZGP. The optimal annealing temperature was 600'C and the optimal annealing time ranged from 200 - 400 h. Annealing in vacuum yielded a larger reduction in the 2-µm optical absorption compared to annealing in the presence of additional zinc and phosphorus vapours. Re-annealing ZGP further reduced the absorption coefficient at 2-µm. However, the percentage decrease in the 2-µm absorption coefficient was much smaller compared to the first thermal anneal.

scholarly journals Synthesis of Ge1−xSnx Alloy Thin Films by Rapid Thermal Annealing of Sputtered Ge/Sn/Ge Layers on Si Substrates

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2248 ◽  
Author(s):  
Hadi Mahmodi ◽  
Md Hashim ◽  
Tetsuo Soga ◽  
Salman Alrokayan ◽  
Haseeb Khan ◽  
...  
Keyword(s):  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Near Infrared ◽  
Annealing Temperature ◽  
Solid Phase ◽  
Infrared Region ◽  
Alloy Formation ◽  
Phase Mixing ◽  
Si Substrates ◽  
Msm Photodetector

In this work, nanocrystalline Ge1−xSnx alloy formation from a rapid thermal annealed Ge/Sn/Ge multilayer has been presented. The multilayer was magnetron sputtered onto the Silicon substrate. This was followed by annealing the layers by rapid thermal annealing, at temperatures of 300 °C, 350 °C, 400 °C, and 450 °C, for 10 s. Then, the effect of thermal annealing on the morphological, structural, and optical characteristics of the synthesized Ge1−xSnx alloys were investigated. The nanocrystalline Ge1−xSnx formation was revealed by high-resolution X-ray diffraction (HR-XRD) measurements, which showed the orientation of (111). Raman results showed that phonon intensities of the Ge-Ge vibrations were improved with an increase in the annealing temperature. The results evidently showed that raising the annealing temperature led to improvements in the crystalline quality of the layers. It was demonstrated that Ge-Sn solid-phase mixing had occurred at a low temperature of 400 °C, which led to the creation of a Ge1−xSnx alloy. In addition, spectral photo-responsivity of a fabricated Ge1−xSnx metal-semiconductor-metal (MSM) photodetector exhibited its extending wavelength into the near-infrared region (820 nm).

Gamma Ray Processing of ZnGeP2: A Nonlinear Optical Material for the Infrared

1994 ◽  
Vol 354 ◽  
Author(s):  
P.G. Schunemann ◽  
P.J. Drevinsky ◽  
M.C. Ohmer
Keyword(s):  
Gamma Rays ◽  
Frequency Conversion ◽  
Near Infrared ◽  
Gamma Ray ◽  
Near Band Edge ◽  
Zinc Germanium Phosphide ◽  
Average Flux ◽  
Loss Coefficients ◽  
Saturation Effects ◽  
Melt Composition

AbstractZinc germanium phosphide, an important frequency-conversion material for producing mid-infrared lasers, is plagued by a defect-related absorption band extending from the fundamental edge (0.62 microns) to ∼3 microns. The level of absorption varies with melt composition, and can be reduced by post-growth annealing treatments. In these experiments, further reduction of the near-band-edge absorption was achieved by irradiating with 1.173 MeV and 1.3325 MeV gamma rays. A 40 kiloCurie “Co source was used to irradiate a series of crystals at an average flux of 4.8x10s rads/hr to cumulative doses up to 3.91xl010 rads. The absorption coefficient in the near-infrared was reduced by nearly a factor of two, and the penetration depth of the ionizing radiation was sufficient to uniformly reduce the absorption in the largest samples tested (up to 7x8x23mm3). The loss coefficients achieved at 1 micron (4.28cm∼l) and at 2.05 microns (0.19cm1) are lower than the best results achievable by conventional thermal annealing alone. No saturation effects or absorption increases at longer wavelengths were observed.

Isothermal crystallization and time-temperature-transformation diagram of the organic semiconductor 5,11-bis(triethylsilylethynyl)anthradithiophene

2021 ◽  
Author(s):  
Liyang Yu ◽  
Andrew M. Zeidell ◽  
John E. Anthony ◽  
Oana D. Jurchescu ◽  
Christian Müller
Keyword(s):  
Electronic Properties ◽  
Thermal Annealing ◽  
Organic Semiconductors ◽  
Organic Semiconductor ◽  
Isothermal Crystallization ◽  
Annealing Temperature ◽  
Trial And Error ◽  
Optimal Annealing Temperature ◽  
Temperature Transformation ◽  
Selection Of

Thermal annealing of organic semiconductors is critical for optimization of their electronic properties. The selection of the optimal annealing temperature –often done on a trial-and-error basis– is essential for achieving...

scholarly journals Влияние термического отжига на свойства многослойных зеркал Mo/Be

2019 ◽  
Vol 89 (11) ◽  
pp. 1783
Author(s):  
Р.М. Смертин ◽  
С.А. Гарахин ◽  
C.Ю. Зуев ◽  
А.Н. Нечай ◽  
Н.В. Полковников ◽  
...  
Keyword(s):  
Reflection Coefficient ◽  
Thermal Annealing ◽  
Annealing Time ◽  
Annealing Temperature ◽  
Thermal Action ◽  
Normal Incidence ◽  
Multilayer Mirrors ◽  
X Ray ◽  
Annealing Conditions ◽  
Reflection Maximum

AbstractThe influence of thermal action on X-ray optics performance and structure of films and transition regions in multilayer Mo/Be mirrors optimized for a reflection maximum in the interval 11.2–11.4 nm at normal incidence has been considered. The annealing temperature reached 300°C and the annealing time was 1 and 4 h. It has been shown that after thermal annealing in vacuum for 1 h at 300°C, the reflection coefficient rises; however, when the annealing time grows to 4 h, it drops. Grains in molybdenum films become finer, and the profiles of transition regions change from exponential to linear. The period of multilayer mirrors has remained the same under all annealing conditions.

Optical Absorption and Photoluminescence in Defect-Stannite-Type Semiconductor ZnGa2Se4

2020 ◽  
Vol 38 ◽  
pp. 10-16
Author(s):  
Shunji Ozaki ◽  
Shingo Mukada
Keyword(s):  
Optical Absorption ◽  
Absorption Coefficient ◽  
Temperature Dependence ◽  
Band Gap ◽  
Brillouin Zone ◽  
Band Edge ◽  
Near Band Edge ◽  
Pl Spectra ◽  
Shrinkage Effect ◽  
Type Semiconductor

Optical absorption and photoluminescence (PL) spectra were measured on defect-stannite-type semiconductor ZnGa2Se4 at temperatures T from 11 to 300 K. The square of the absorption coefficient spectra showed distinct two absorption edges, which were E0A,B and E0C,D transitions at Γ point in the Brillouin zone. The temperature dependence of the direct-gap energies, E0A,B and E0C,D, of ZnGa2Se4 were determined and fit using the analytical four-parameter expression developed for the explanation of the band-gap shrinkage effect in semiconductors. The PL emissions at near band-edge and at higher energy than band-edge were also observed at T ≤ 150 K.

scholarly journals Intrinsic Defect Engineering in Eu3+ Doped ZnWO4 for Annealing Temperature Tunable Photoluminescence

Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 99 ◽  
Author(s):  
Bao-gai Zhai ◽  
Long Yang ◽  
Yuan Huang
Keyword(s):  
Optical Absorption ◽  
Thermal Annealing ◽  
Density Functional ◽  
Annealing Temperature ◽  
Intrinsic Defect ◽  
Defect Engineering ◽  
Intrinsic Defects ◽  
X Ray ◽  
Color Tunable ◽  
Co Precipitation

Eu3+ doped ZnWO4 phosphors were synthesized via the co-precipitation technique followed by subsequent thermal annealing in the range of 400–1000 °C. The phase, morphology, elemental composition, chemical states, optical absorption, and photoluminescence (PL) of the phosphors were characterized by X-ray diffraction, scanning electron microscopy, dispersive X-ray spectroscopy, X-ray photoelectron spectrometry, diffuse UV–vis reflectance spectroscopy, PL spectrophotometry, and PL lifetime spectroscopy, respectively. It is found that the PL from Eu3+ doped ZnWO4 is tunable through the control of the annealing temperature. Density functional calculations and optical absorption confirm that thermal annealing created intrinsic defects in ZnWO4 lattices play a pivotal role in the color tunable emissions of the Eu3+ doped ZnWO4 phosphors. These data have demonstrated that intrinsic defect engineering in ZnWO4 lattice is an alternative and effective strategy for tuning the emission color of Eu3+ doped ZnWO4. This work shows how to harness the intrinsic defects in ZnWO4 for the preparation of color tunable light-emitting phosphors.

Correlation between crystallinity and mid-infrared optical absorption spectra of silicon supersaturated with sulfur

2015 ◽  
Vol 1738 ◽  
Author(s):  
Ikurou Umezu ◽  
Katsuki Nagao ◽  
Tatsuya Nakai ◽  
Muneyuki Naito ◽  
Mitsuru Inada ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Single Crystal ◽  
Thermal Annealing ◽  
Laser Fluence ◽  
Annealing Temperature ◽  
Pulsed Laser ◽  
Single Crystal Substrate ◽  
Laser Melting ◽  
Mid Infrared ◽  
Insulator Metal Transition

ABSTRACTWe prepared silicon hyperdoped with sulfur by ion-implantation followed by pulsed laser melting. Effects of laser fluence during pulsed laser melting and of post-annealing on the silicon hyperdoped with sulfur are investigated. The structure of hyperdoped layer changes from poly-to mono-crystal with increasing laser fluence. Interface between sulfur-implanted-layer and single-crystal substrate disappear above 1.1 J/cm2. The spectral intensity of mid-infrared (MIR) optical absorption increases with crystallinity and spectral shape depends on whether the melt depth during pulsed laser melting reaches interface between implanted layer and single-crystal silicon substrate or not. The MIR absorption intensity rapidly decreases with thermal annealing temperature and almost disappears at 750 °C. The activation energy of conductivity decreases with increasing laser fluence and further decreases with increasing post thermal-annealing temperature. The insulator-metal transition is observed for the sample annealed at 750 °C. These results indicate that there is no direct correlation between MIR optical absorption band and insulator-metal transition.

Optical Absorption Spectroscopy of DNA-Wrapped HiPco Carbon Nanotubes

2019 ◽  
Vol 943 ◽  
pp. 95-99
Author(s):  
Li Jun Wang ◽  
Kazuo Umemura
Keyword(s):  
Carbon Nanotubes ◽  
Aqueous Solution ◽  
Optical Absorption ◽  
Absorption Spectroscopy ◽  
Near Infrared ◽  
Nir Spectroscopy ◽  
Optical Characterization ◽  
Optical Absorption Spectroscopy ◽  
Double Stranded Dna

Optical absorption spectroscopy provides evidence for individually dispersed carbon nanotubes. A common method to disperse SWCNTs into aqueous solution is to sonicate the mixture in the presence of a double-stranded DNA (dsDNA). In this paper, optical characterization of dsDNA-wrapped HiPco carbon nanotubes (dsDNA-SWCNT) was carried out using near infrared (NIR) spectroscopy and photoluminescence (PL) experiments. The findings suggest that SWCNT dispersion is very good in the environment of DNA existing. Additionally, its dispersion depends on dsDNA concentration.

scholarly journals Satellite monitoring of different vegetation types by differential optical absorption spectroscopy (DOAS) in the red spectral range

2007 ◽  
Vol 7 (1) ◽  
pp. 69-79 ◽  
Author(s):  
T. Wagner ◽  
S. Beirle ◽  
T. Deutschmann ◽  
M. Grzegorski ◽  
U. Platt
Keyword(s):  
Optical Absorption ◽  
Absorption Spectroscopy ◽  
Spectral Range ◽  
Near Infrared ◽  
Vegetation Type ◽  
Differential Optical Absorption Spectroscopy ◽  
Trace Gas ◽  
Satellite Monitoring ◽  
Optical Absorption Spectroscopy ◽  
Vegetation Types

Abstract. A new method for the satellite remote sensing of different types of vegetation and ocean colour is presented. In contrast to existing algorithms relying on the strong change of the reflectivity in the red and near infrared spectral region, our method analyses weak narrow-band (few nm) reflectance structures (i.e. "fingerprint" structures) of vegetation in the red spectral range. It is based on differential optical absorption spectroscopy (DOAS), which is usually applied for the analysis of atmospheric trace gas absorptions. Since the spectra of atmospheric absorption and vegetation reflectance are simultaneously included in the analysis, the effects of atmospheric absorptions are automatically corrected (in contrast to other algorithms). The inclusion of the vegetation spectra also significantly improves the results of the trace gas retrieval. The global maps of the results illustrate the seasonal cycles of different vegetation types. In addition to the vegetation distribution on land, they also show patterns of biological activity in the oceans. Our results indicate that improved sets of vegetation spectra might lead to more accurate and more specific identification of vegetation type in the future.

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