Study of structural, elastic, electronic, dynamical and optical properties of beryllium selenide (BeSe) semiconductor in zinc blend and NiAs phases

Cadmium Selenide (CdSe) thin films were prepared by pulsed laser deposition using a Nd:YAG laser (355 nm). Films were grown by ablating a sintered pure CdSe target with fluences from 0.1 to 1.5 J/cm2 on corning glass, silicon (100) and quartz substrates. Deposition chamber was maintained under vacuum pressure while substrate temperature was increased from room temperature to 500°C in order to control the crystalline phase. All the films show mirror-like surface morphology. Atomic force microscopy (AFM) images shown that films have very flat surfaces with RMS values around 0.7 and 5 nm for room temperature and 500°C respectively. The X-ray diffraction analysis proves the presence of the cubic zinc blend phase for the CdSe films deposited at low temperature, at 400°C and at higher substrate temperature the hexagonal phase is present. TEM analysis shows that at 100°C the films are constituted by particles with an average size of 30nm in diameter. The optical properties of the films were determined from the UV-transmission spectra. The estimated band gap values of the films deposited at room temperature and at 400°C (0.1 J/cm2) were 1.87 and 1.70 eV respectively.

Download Full-text

Structural, morphological and optical properties of Mn doped ZnS nanocrystals

Cerâmica ◽

10.1590/s0366-69132013000400019 ◽

2013 ◽

Vol 59 (352) ◽

pp. 614-619 ◽

Cited By ~ 31

Author(s):

V. D. Mote ◽

Y. Purushotham ◽

B. N. Dole

Keyword(s):

Optical Properties ◽

Average Particle Size ◽

Chemical Species ◽

Average Particle ◽

Secondary Phases ◽

Zinc Blend ◽

Composition Formula ◽

Xrd Patterns ◽

Mn Concentration ◽

Mn Doped

Mn doped ZnS samples with composition formula Zn1-xMn xS where x = 0, 0.02, 0.05 and 0.10 were prepared by chemical method. Samples characterized for its structural, morphological and optical properties by X-ray diffraction (XRD), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR) and UV-vis spectrometry. XRD patterns confirm cubic zinc blend structure with no secondary phases for pure and Mn doped ZnS. Lattice constant value increases slightly with Mn concentration due to the substitution of Mn in ZnO lattice. TEM images show that the particles have spherical in shape with an average particle size 3-4 nm. The chemical species of the grown crystals are identified by FTIR spectra. Optical absorption spectra show decrement in band gap with increasing Mn concentration.

Download Full-text

Structural, morphological and optical properties of Mn doped ZnS nanocrystals

Cerâmica ◽

10.1590/s0366-69132013000300008 ◽

2013 ◽

Vol 59 (351) ◽

pp. 395-400 ◽

Cited By ~ 11

Author(s):

V. D. Mote ◽

Y. Purushotham ◽

B. N. Dole

Keyword(s):

Optical Properties ◽

Average Particle Size ◽

Chemical Species ◽

Average Particle ◽

Secondary Phases ◽

Zinc Blend ◽

Composition Formula ◽

Xrd Patterns ◽

Mn Concentration ◽

Mn Doped

Mn doped ZnS samples with composition formula Zn1-xMn xS where x = 0.00, 0.02, 0.05 and 0.10 were prepared by chemical method. Samples characterized for its structural, morphological and optical properties by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and UV-vis spectrometer. XRD patterns confirm cubic zinc blend structure with no secondary phases for pure and Mn doped ZnS. Lattice constant value increases slightly with Mn concentration due to the substitution of Mn in ZnS lattice. TEM images show that the particles have spherical in shape with an average particle size between 3-4 nm. The chemical species of the grown crystals are identified by FTIR spectra. Optical absorption spectra show decrement in band gap with increasing Mn concentration.

Download Full-text

Pressure Effect on Structural, Electronic and optical properties of Zinc blend MgO solid solution

Advances in Materials Science and Applications ◽

10.5963/amsa0101002 ◽

2012 ◽

Vol 1 (1) ◽

pp. 9-12 ◽

Cited By ~ 2

Author(s):

A. Abdiche Abdiche ◽

R. Riane ◽

M. Guemou ◽

Y. Al-Douri ◽

R. Baghdad ◽

...

Keyword(s):

Solid Solution ◽

Optical Properties ◽

Pressure Effect ◽

Zinc Blend ◽

Electronic And Optical Properties

Download Full-text

Design of objective lens for 200-kV high-resolution electron microscopes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100075361 ◽

1983 ◽

Vol 41 ◽

pp. 314-315

Author(s):

K. Tsuno ◽

T. Honda ◽

Y. Harada ◽

M. Naruse

Keyword(s):

Optical Properties ◽

Computer Technology ◽

Axial Magnetic Field ◽

Chromatic Aberration ◽

Objective Lens ◽

Resolution Electron ◽

Correction Of Astigmatism ◽

Three Stages ◽

Electron Microscopes ◽

Stage 1

Developement of computer technology provides much improvements on electron microscopy, such as simulation of images, reconstruction of images and automatic controll of microscopes (auto-focussing and auto-correction of astigmatism) and design of electron microscope lenses by using a finite element method (FEM). In this investigation, procedures for simulating the optical properties of objective lenses of HREM and the characteristics of the new lens for HREM at 200 kV are described.The process for designing the objective lens is divided into three stages. Stage 1 is the process for estimating the optical properties of the lens. Firstly, calculation by FEM is made for simulating the axial magnetic field distributions Bzc of the lens. Secondly, electron ray trajectory is numerically calculated by using Bzc. And lastly, using Bzc and ray trajectory, spherical and chromatic aberration coefficients Cs and Cc are numerically calculated. Above calculations are repeated by changing the shape of lens until! to find an optimum aberration coefficients.

Download Full-text

Optical Properties of HVEM Accelerators

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100114529 ◽

1975 ◽

Vol 33 ◽

pp. 180-181

Author(s):

A. Strojnik ◽

J.W. Scholl ◽

V. Bevc

Keyword(s):

Optical Properties ◽

Electron Accelerator ◽

Systematic Investigation ◽

Electron Source ◽

High Brightness ◽

The Past ◽

Wide Range ◽

Optical Behavior

The electron accelerator, as inserted between the electron source (injector) and the imaging column of the HVEM, is usually a strong lens and should be optimized in order to ensure high brightness over a wide range of accelerating voltages and illuminating conditions. This is especially true in the case of the STEM where the brightness directly determines the highest resolution attainable. In the past, the optical behavior of accelerators was usually determined for a particular configuration. During the development of the accelerator for the Arizona 1 MEV STEM, systematic investigation was made of the major optical properties for a variety of electrode configurations, number of stages N, accelerating voltages, 1 and 10 MEV, and a range of injection voltages ϕ0 = 1, 3, 10, 30, 100, 300 kV).

Download Full-text

Differential polarization imaging of sickled cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100102390 ◽

1988 ◽

Vol 46 ◽

pp. 62-63

Author(s):

Marcos F. Maestre

Keyword(s):

Optical Properties ◽

Theoretical Approach ◽

Polarized Light ◽

Polarization Microscopy ◽

Spectroscopic Techniques ◽

Polarization Imaging ◽

Circularly Polarized Light ◽

Circularly Polarized ◽

Microscopic Scale ◽

Chiral Structures

Recently we have developed a form of polarization microscopy that forms images using optical properties that have previously been limited to macroscopic samples. This has given us a new window into the distribution of structure on a microscopic scale. We have coined the name differential polarization microscopy to identify the images obtained that are due to certain polarization dependent effects. Differential polarization microscopy has its origins in various spectroscopic techniques that have been used to study longer range structures in solution as well as solids. The differential scattering of circularly polarized light has been shown to be dependent on the long range chiral order, both theoretically and experimentally. The same theoretical approach was used to show that images due to differential scattering of circularly polarized light will give images dependent on chiral structures. With large helices (greater than the wavelength of light) the pitch and radius of the helix could be measured directly from these images.

Download Full-text