Effects of pH Value on the Structures and Optical Properties of Bi2S3 Thin Films

2010 ◽  
Vol 434-435 ◽  
pp. 397-399
Author(s):  
Jian Feng Huang ◽  
Yan Wang ◽  
Li Yun Cao ◽  
Hui Zhu ◽  
Xie Rong Zeng
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Room Temperature ◽  
Light Emission ◽  
Ph Value ◽  
Solution Ph ◽  
Oriented Growth ◽  
Cathodic Electrodeposition ◽  
Ph Values ◽  
Effects Of Ph

Bismuth sulfide (Bi2S3) is an important semiconductor material, which has wide applications in thermoelectricity, electronics, photoelectricity and infrared spectroscopy. Bi2S3 thin films have been deposited on ITO substrates through a cathodic electrodeposition approach at room temperature. The as-deposited thin films were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM) and photoluminescence spectrum (PL). The effects of solution pH values on the structures and optical properties of the thin films were particularly investigated. Results show that uniform Bi2S3 thin films with oriented growth along (240) direction can be obtained at the solution pH value range from 4.5 to 6.5. The as-prepared thin films exhibit stable blue-green photoluminescence properties under the ultraviolet light excitation at room temperature. With the increase of the solution pH values, the crystallization of the Bi2S3 thin films improves while the grain size of the obtained thin films decreases and the light emission intensity of the thin films decreases.

Influence of pH Value on the Phases, Morphologies and Optical Properties of Sm2S3 Thin Films

2012 ◽  
Vol 512-515 ◽  
pp. 368-371
Author(s):  
Yan Chao Hou ◽  
Jian Feng Huang ◽  
Li Yun Cao ◽  
Jian Peng Wu
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Ph Value ◽  
Visible Spectrum ◽  
X Ray Diffraction ◽  
Solution Ph ◽  
Oriented Growth ◽  
Force Microscopy ◽  
Atomic Force ◽  
Surface Morphologies

Sm2S3 thin films were prepared on Si (100) substrates by liquid phase self–assemble method. The influences of solution pH value on the phases, surface morphologies and optical properties of the as deposited films were investigated. The as–deposited Sm2S3 thin films were characterized by X–ray diffraction (XRD), atomic force microscopy (AFM) and ultraviolet-visible (UV–Vis). Results indicate that Sm2S3 thin film with oriented growth along (105) direction can be obtained at pH value of 3.0, deposition temperature of 80 °C, following deposition for 24 h. The grain sizes of the Sm2S3 first increase and then decrease with increasing pH value. The as–deposited thin films exhibit a dense and crystallinized surface morphology. The film shows good transmittance in visible spectrum and excellent absorbency of ultraviolet light, and the bandgap of the thin films at pH of 3.0 is calculated to be 4.06 eV.

Effects of pH Values on the Structure, Composition and Luminescence of CaWO4:Tb3+ Thin Films

2012 ◽  
Vol 531-532 ◽  
pp. 204-207
Author(s):  
Lian Ping Chen ◽  
Yuan Hong Gao
Keyword(s):  
Thin Films ◽  
Ph Value ◽  
Electrochemical Techniques ◽  
Luminescent Properties ◽  
X Ray Diffraction ◽  
Step Method ◽  
X Ray ◽  
Ph Values ◽  
Effects Of Ph ◽  
Rare Earth Doped

It is hardly possible to obtain rare earth doped CaWO4thin films directly through electrochemical techniques. A two-step method has been proposed to synthesize Tb3+-doped CaWO4thin films. X-ray diffraction, energy dispersive X-ray analysis, spectrophotometer were used to characterize their phase, composition and luminescent properties. Results reveal that Tb3+-doped CaWO4films have a tetragonal phase. The ratio of n(Tb)/[n(Ca)+n(Tb)+n(Na)] decreases with the increase of pH value of TbCl3solutions. When the pH value (adjusted by NaOH) is higher than 5, Na element has been detected in CaWO4:Tb3+thin films. Based on the analysis on the composition and luminescence, it can be concluded that the pH value of TbCl3solutions must be no higher than 9.1, otherwise, no Tb3+-doped CaWO4thin films can be obtained. Under the excitation of 237 nm, sharp emission peaks at 543 and 489 nm have been observed for Tb3+-doped CaWO4:Tb3+thin films.

scholarly journals Producing Drink like Grafted Milk from Chickpeas and Evaluation of its Qualitative Properties

2020 ◽  
Vol 10 (03) ◽  
pp. 374-377
Author(s):  
Ibtihal Ismail Muhammad Al-Ani
Keyword(s):  
Room Temperature ◽  
Extraction Efficiency ◽  
Ph Value ◽  
Bacterial Number ◽  
Qualitative Properties ◽  
Product Density ◽  
Ph Values ◽  
Extraction Volume ◽  
Refrigerator Temperature ◽  
Soda Solution

The present study aimed to study the possibility of producing a drink that looks like grafted milk by using chickpeas and evaluate its physical, chemical, microbial, and sensory properties. The result showed the superiority of F treatment (soaking 100 grams of chickpeas at the refrigerator temperature 4ºC for 12 hours) over the rest seven treatments in extraction efficiency, which was 70%, while, it was 50.5% in H treatment (soaking 100 grams of chickpeas in the heated water at 60ºC for 30 minutes). The highest value of the product density was after water and flavorings addition in the D treatment (soaking 100 grams chickpeas in 0.05 soda solution at 60ºC for 30 minutes), and it was 0.97 g cm-3, compared with the lowest density 0.57 g cm-3 in A treatment (soaking 100 grams chickpeas in 0.05 soda solution at room temperature 25ºC for 12 hours). pH values were highest in A treatment compared with the other treatments, and its value was 7.66 in the 1st and 2nd day, after dissolving in a refrigerator at 4ºC, and then, for 5 minutes at room temperature 30ºC. The lowest value in the D treatment was 6.45 on the 1st day, and 6.87 on the 2nd day in the G treatment. On the 3rd day, the highest pH value was 7.13 in the D treatment, and the lowest value 6.79 was in the E treatment. pH highest value was 6.2 on the 4th day in A treatment. From the last results, it may be concluded that F treatment was the best in extraction efficiency, the final product density, and less total bacterial number, after dissolving for 5 days at refrigerator temperature 4ºC, and then, at room temperature 30ºC for 3 and 48 hours incubation. The best extraction volume and pH were in A treatment.

Optical Properties of Alq3/TiO2 BDR Structure Processed by Spin Coating Technique

MRS Advances ◽  
2019 ◽  
Vol 4 (11-12) ◽  
pp. 661-666
Author(s):  
L. Ajith DeSilva ◽  
Sarahn Nazaret ◽  
A. G. U. Perera ◽  
T. M. W. J. Bandara
Keyword(s):  
Thin Films ◽  
Titanium Dioxide ◽  
Optical Properties ◽  
Band Gap ◽  
Spin Coating ◽  
Light Emission ◽  
Wide Band ◽  
Bragg Reflector ◽  
Distributed Bragg Reflector ◽  
Pl Quenching

ABSTRACTOne-dimensional hybrid Distributed Bragg Reflector (DBR) is constructed using Tris (8-hydroxy) quinoline aluminum (Alq3) molecules and Titanium dioxide (TiO2) nanoparticles via spin coating process. Light emission from thin films of low molecular weight organic semiconductor of Alq3 is dominated by excitons. This material has been widely used as a superior emitter for organic light emitting diodes. Titanium dioxide (TiO2) is an inorganic semiconductor with a high band gap. Photoluminescence (PL) of thin films of Alq3 showed a broad PL peak at 530 nm. In DBR structures, PL quenching is observed but there is no shift in the PL peak of the Alq3. The PL quenching is tentatively attributed to energy transfer via sensitization to wide band gap TiO2 layers. A simple excitonic model is suggested to explain the observation. Fabrication process and optical properties of the structure are presented.

Study on Extraction Technology and Stability of Melanin from Banana Peel

2013 ◽  
Vol 815 ◽  
pp. 287-292
Author(s):  
Li Jing Min ◽  
Jing Fen Li
Keyword(s):  
Metal Ions ◽  
Light Source ◽  
Room Temperature ◽  
Ph Value ◽  
Orthogonal Test ◽  
Raw Material ◽  
Banana Peel ◽  
Extraction Temperature ◽  
Solution Ph ◽  
Extraction Technology

[Objectiv The aim is to study the extraction technology of melanin from banana peel, and discuss its stability. [Metho We used banana peel as raw material, the absorbance at 410 nm as the index, extracted melanin by base-acid method, and optimized the extraction technology by the single factor and orthogonal test. Then we discussed the melanins stability at different temperature, light source, pH value, metal ions, antioxidant and reducing agents.[Result The best extraction conditions of melanin is that, hydrochloric acid soak time 5 h, alkaline solution pH value 14, extracting time 20 min, extraction temperature 70 °C, absorbance value about 0.309 A. Melanin from banana peel is stable at high temperature, different light source irradiation, reducing agent coexist; but at room temperature, metal ions and oxidizing agent coexist, it is unstable. [Conclusio This study provided experimental basis for the optimization and development of melanin from banana peel.

scholarly journals Optical and magneto-optical properties of GdxFe(100-x) thin films close to the compensation point

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Eva Jesenská ◽  
Takayuki Ishibashi ◽  
Lukáš Beran ◽  
Martin Pavelka ◽  
Jaroslav Hamrle ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Spectral Dependence ◽  
Room Temperature ◽  
Magnetic Moments ◽  
Perpendicular Magnetic Anisotropy ◽  
Theoretical Models ◽  
Compensation Point ◽  
Spin Torque ◽  
Dc Sputtering

Abstract Unlike ferromagnetic materials, ferrimagnetic metals have recently received considerable attention due to their bulk perpendicular magnetic anisotropy, low net magnetization and tunable magnetic properties. This makes them perfect candidates for the research of recently discovered spin-torque related phenomena. Among other ferrimagnetic metals, GdFe has an advantage in relatively large magnetic moments in both sublattices and tunability of compensation point above the room temperature by small changes in its composition. We present a systematic study of optical and magneto-optical properties of amorphous GdxFe(100-x) thin films of various compositions (x = 18.3, 20.0, 24.7, 26.7) prepared by DC sputtering on thermally oxidized SiO2 substrates. A combination of spectroscopic ellipsometry and magneto-optical spectroscopy in the photon energy range from 1.5 to 5.5 eV with advanced theoretical models allowed us to deduce the spectral dependence of complete permittivity tensors across the compensation point. Such information is important for further optical detection of spin related phenomena driven by vicinity of compensation point in nanostructures containing GdFe.

Room-temperature synthesis and optical properties of nanostructured Ba-Doped ZnO thin films

2019 ◽  
Vol 130 ◽  
pp. 321-331 ◽  
Author(s):  
C.C. Okorieimoh ◽  
Ugochi Chime ◽  
Agnes C. Nkele ◽  
Assumpta C. Nwanya ◽  
Itani Given Madiba ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Room Temperature ◽  
Zno Thin Films ◽  
Temperature Synthesis ◽  
Room Temperature Synthesis ◽  
Doped Zno

scholarly journals The Structural, Electronic, and Optical Properties of Ge/Si Quantum Wells: Lasing at a Wavelength of 1550 nm

Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 1006
Author(s):  
Hongqiang Li ◽  
Jianing Wang ◽  
Jinjun Bai ◽  
Shanshan Zhang ◽  
Sai Zhang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Quantum Wells ◽  
Room Temperature ◽  
Light Emission ◽  
Single Mode ◽  
Group Iv ◽  
Light Power ◽  
Fully Integrated ◽  
Electronic And Optical Properties ◽  
Novel Approach

The realization of a fully integrated group IV electrically driven laser at room temperature is an essential issue to be solved. We introduced a novel group IV side-emitting laser at a wavelength of 1550 nm based on a 3-layer Ge/Si quantum well (QW). By designing this scheme, we showed that the structural, electronic, and optical properties are excited for lasing at 1550 nm. The preliminary results show that the device can produce a good light spot shape convenient for direct coupling with the waveguide and single-mode light emission. The laser luminous power can reach up to 2.32 mW at a wavelength of 1550 nm with a 300-mA current. Moreover, at room temperature (300 K), the laser can maintain maximum light power and an ideal wavelength (1550 nm). Thus, this study provides a novel approach to reliable, efficient electrically pumped silicon-based lasers.

Effect of pH on the structural and optical properties of polycrystalline ZnSe thin films produced by CBD method

2019 ◽  
Vol 33 (05) ◽  
pp. 1950024 ◽  
Author(s):  
Fatma Meydaneri Tezel ◽  
İ. Afşin Kariper
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Room Temperature ◽  
Dielectric Constants ◽  
Structural And Optical Properties ◽  
Polycrystalline Structure ◽  
Density Values ◽  
Cbd Method ◽  
Znse Thin Films ◽  
Absorbance Spectra

In this study, zinc selenide (ZnSe) thin films were produced on glass substrate by using chemical bath deposition (CBD) method at 80[Formula: see text]C, from aqueous solutions of zinc sulphate and sodium selenosulphide, which were produced using solid selenium as the selenium source. The optical and structural properties of ZnSe thin films were investigated at room-temperature. The pH of the chemical bath, in which ZnSe thin films were immersed, were changed between pH:8–11. Optical properties of the films, including extinction coefficient, refractive index, reflectance, absorbance, transmittance, dielectric constants and optical density values were calculated using absorbance and transmittance measurements determined using a Hach Lange 500 spectrophotometer, in 300–1100 nm wavelength range. Optical bandgap values were obtained from transmittance and absorbance spectra ranged between 2.12 and 2.49 eV. According to XRD results, it was found that the films have polycrystalline structure and they exhibited different film thicknesses depending on phase and pH changes.

scholarly journals Optical properties of CuSe thin films - band gap determination

2017 ◽  
Vol 49 (2) ◽  
pp. 167-174 ◽  
Author(s):  
Milica Petrovic ◽  
Martina Gilic ◽  
Jovana Cirkovic ◽  
Maja Romcevic ◽  
Nebojsa Romcevic ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Room Temperature ◽  
Nir Spectroscopy ◽  
Copper Selenide ◽  
Photoluminescence Spectra ◽  
Indirect Transition ◽  
Direct Transition ◽  
Scanning Electron

Copper selenide thin films of three different thicknesses have been prepared by vacuum evaporation method on a glass substrate at room temperature. The optical properties of the films were investigated by UV-VIS-NIR spectroscopy and photoluminescence spectroscopy. Surface morphology was investigated by field-emission scanning electron microscopy. Copper selenide exhibits both direct and indirect transitions. The band gap for direct transition is found to be ~2.7 eV and that for indirect transition it is ~1.70 eV. Photoluminescence spectra of copper selenide thin films have also been analyzed, which show emission peaks at 530, 550, and 760 nm. The latter corresponds to indirect transition in investigated material.

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