Band Gap Engineering in β-Ga2O3 for a High-Performance X-ray Detector

2021 ◽  
Author(s):  
Zhiwei Li ◽  
Jiawen Chen ◽  
Huili Tang ◽  
Zhichao Zhu ◽  
Mu Gu ◽  
...  
Keyword(s):  
Band Gap ◽  
High Performance ◽  
Band Gap Engineering ◽  
X Ray

Band-gap engineering in amorphous/microcrystalline ScxGa1-xN.

2001 ◽  
Vol 693 ◽  
Author(s):  
M. E. Little ◽  
M. E. Kordesch
Keyword(s):  
Optical Absorption ◽  
Band Gap ◽  
Absorption Spectra ◽  
Optical Band Gap ◽  
Optical Absorption Spectra ◽  
X Ray Diffraction ◽  
Band Gap Engineering ◽  
X Ray ◽  
Bilayer Films ◽  
Quartz Substrates

AbstractReactive sputtering was used to grow thin films of ScxGa1-xN with scandium concentrations of 20%-70% on quartz substrates at temperatures of 300-675 K. X-ray diffraction (XRD) of the films showed either weak or no structure, suggesting the films are amorphous or microcrystalline. Optical absorption spectra were taken of each sample and the optical band gap was determined. The band gap varied linearly with increasing Ga concentration between 2.0 and 3.5 eV. Ellipsometry was used to confirm the band gap measurements and provide optical constants in the range 250-1200 nm. ScN and GaN have different crystal structures (rocksalt and wurzite, respectively), and thus may form a heterogeneous mixture as opposed to an alloy. Since the XRD data were inconclusive, bilayers of ScN/GaN were grown and optical absorption spectra taken. A fundamental difference in the spectra between the bilayer films and alloy films was seen, suggesting the films are alloys, not herterogeneous mixtures.

scholarly journals Size- and Temperature-control Optical Direct/indirect Band Tuning in Layered Compounds: Band Gap Engineering

2021 ◽  
Author(s):  
M. Miah
Keyword(s):  
Grain Size ◽  
Band Gap ◽  
Layered Compounds ◽  
Exciting Light ◽  
Interband Transitions ◽  
X Ray Diffraction ◽  
Band Gap Engineering ◽  
X Ray ◽  
Direct Band ◽  
Varshni Relation

Abstract The X-ray diffraction (XRD) is studied in thermally evaporated cadmium iodide (CdI2) thin films with various thicknesses. The grain size, calculated from the XRD, is found to increase with increasing the thickness of the film, while the reflectivity and refractive index decease with increasing the wavelength of the exciting light. The optical absorption spectra show both allowed direct and indirect interband transitions across a fundamental gap in CdI2. It is found that both indirect and direct band gap (Eg) decrease with increasing the thickness of the film and that the indirect Eg is lower than the direct Eg by an amount of about 0.7 eV. The direct Eg is also decreased with increasing both the grain size and temperature. However, the temperature dependence of Eg follows the Varshni relation. Our results highlight the possibility of engineering or tuning the Eg of CdI2 by controlling the thickness of the film, grain size as well as temperature.

Band-Gap Engineering of FeF3·0.33H2O Nanosphere via Ni Doping as a High-Performance Lithium-Ion Battery Cathode

2020 ◽  
Vol 8 (41) ◽  
pp. 15651-15660
Author(s):  
Min Liu ◽  
Qun Wang ◽  
Biaobing Chen ◽  
Huiling Lei ◽  
Lei Liu ◽  
...  
Keyword(s):  
Band Gap ◽  
Lithium Ion Battery ◽  
High Performance ◽  
Lithium Ion ◽  
Ni Doping ◽  
Band Gap Engineering

scholarly journals Growth and Characterization of Polycrystalline Silicon Thin Films for Photocatalytic Splitting of Water in Oxide-Si Tandem Cells

2020 ◽  
Author(s):  
Ali Zahid ◽  
Umer Zahid ◽  
Aamir Hasan ◽  
Muhammad Khuldoon
Keyword(s):  
Band Gap ◽  
Fossil Fuels ◽  
Crystalline Silicon ◽  
X Ray Diffraction ◽  
Active Electrode ◽  
Band Gap Engineering ◽  
X Ray ◽  
Silicon Thin Films ◽  
Deposition Parameters

With the decline in fossil fuels, hydrogen-based alternatives provide a reliable and clean source for sustainable energy generation. In these endeavors, photochemical splitting for hydrogen production through tandem cells has been the source of much theoretical and experimental research in science. Much focus has been placed on interfacial band gap engineering as one of the most promising routes in the generation of hydrogen.This present work explores sputtering of n-silicon to form the active electrode in a n-Si | n-TiO2 tandem cell and investigates the effect of variations in sputtering and post sputtering treatment parameters (rapid thermal annealing and long cycle annealing) for successful deposition of crystalline Silicon. The samples were successfully characterized via Raman Spectroscopy, X-ray Diffraction and Optical Transmission Spectroscopy to ascertain prevalent crystalline order and optical band gap, under different sputtering and post-sputtering conditions. Relevant conclusions were drawn to ascertain the best possible deposition parameters of n-Si for photocatalytic water splitting.

Crystal defect-mediated band-gap engineering: a new strategy for tuning the optical properties of Ag2Se quantum dots toward enhanced hydrogen evolution performance

2015 ◽  
Vol 3 (40) ◽  
pp. 20051-20055 ◽  
Author(s):  
Qi Cao ◽  
Yi-Feng Cheng ◽  
Han Bi ◽  
Xuebing Zhao ◽  
Kaiping Yuan ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Visible Light ◽  
Band Gap ◽  
Hydrogen Evolution ◽  
High Performance ◽  
Crystal Defect ◽  
Band Gap Engineering ◽  
New Strategy ◽  
Visible Light Driven

Defect-rich Ag2Se QDs were prepared controllably for sensitizing TiO2 toward high-performance visible-light-driven hydrogen-evolution photocatalysts.

Macroprobe Mode for the Study of Segregation in Steels

1990 ◽  
Vol 48 (2) ◽  
pp. 260-261
Author(s):  
Auclair Gilles ◽  
Benoit Danièle
Keyword(s):  
Mechanical Properties ◽  
Spatial Distribution ◽  
High Performance ◽  
Volume Fraction ◽  
Sheet Steel ◽  
Acquisition Time ◽  
Chemical Information ◽  
X Ray ◽  
Accurate Quantitative Analysis ◽  
Optical Micrographs

During these last 10 years, high performance correction procedures have been developed for classical EPMA, and it is nowadays possible to obtain accurate quantitative analysis even for soft X-ray radiations. It is also possible to perform EPMA by adapting this accurate quantitative procedures to unusual applications such as the measurement of the segregation on wide areas in as-cast and sheet steel products.The main objection for analysis of segregation in steel by means of a line-scan mode is that it requires a very heavy sampling plan to make sure that the most significant points are analyzed. Moreover only local chemical information is obtained whereas mechanical properties are also dependant on the volume fraction and the spatial distribution of highly segregated zones. For these reasons we have chosen to systematically acquire X-ray calibrated mappings which give pictures similar to optical micrographs. Although mapping requires lengthy acquisition time there is a corresponding increase in the information given by image anlysis.

PHAX-SCAN: Functional integration of a Scanning Electron Microscope and an energy-dispersive x-ray analyser

1989 ◽  
Vol 47 ◽  
pp. 56-57
Author(s):  
Marc H. Peeters ◽  
Max T. Otten
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
High Speed ◽  
High Performance ◽  
Functional Integration ◽  
Energy Dispersive ◽  
X Rays ◽  
X Ray ◽  
High Speed Analysis ◽  
Scanning Electron

Over the past decades, the combination of energy-dispersive analysis of X-rays and scanning electron microscopy has proved to be a powerful tool for fast and reliable elemental characterization of a large variety of specimens. The technique has evolved rapidly from a purely qualitative characterization method to a reliable quantitative way of analysis. In the last 5 years, an increasing need for automation is observed, whereby energy-dispersive analysers control the beam and stage movement of the scanning electron microscope in order to collect digital X-ray images and perform unattended point analysis over multiple locations.The Philips High-speed Analysis of X-rays system (PHAX-Scan) makes use of the high performance dual-processor structure of the EDAX PV9900 analyser and the databus structure of the Philips series 500 scanning electron microscope to provide a highly automated, user-friendly and extremely fast microanalysis system. The software that runs on the hardware described above was specifically designed to provide the ultimate attainable speed on the system.

Sign in / Sign up

Export Citation Format

Share Document