Application of Fresnel diffraction from a phase step to the measurement of film thickness

2009 ◽  
Vol 48 (29) ◽  
pp. 5497 ◽  
Author(s):  
Mohammad Taghi Tavassoly ◽  
Iman Moaddel Haghighi ◽  
Khosrow Hassani
2021 ◽  
Vol 127 (8) ◽  
Author(s):  
Ahad Saber ◽  
Mohammad Taghi Tavassoly ◽  
Rasoul Aalipour

2018 ◽  
Vol 20 (9) ◽  
pp. 095606 ◽  
Author(s):  
Khosrow Hassani ◽  
Ameneh Jabbari ◽  
Mohammad Taghi Tavassoly

2005 ◽  
Vol 255 (1-3) ◽  
pp. 23-34 ◽  
Author(s):  
M.T. Tavassoly ◽  
M. Amiri ◽  
E. Karimi ◽  
H.R. Khalesifard

2021 ◽  
Author(s):  
Ahad Saber ◽  
Mohammad Taghi Tavassoly ◽  
Rasoul Aalipour

Abstract Fresnel diffraction from a phase step for measuring diffusion coefficient in transparent liquids is investigated. When a transparent glass plate immersed vertically in a cell containing two diffusing liquids is illuminated by a parallel beam of light, the diffraction pattern of the plate edge forms on a screen perpendicular to the beam direction and varies by diffusion. The gradient of the refractive index in the liquids is then obtained by analyzing the diffraction patterns at different times after the beginning of the diffusion process, from which the diffusion coefficient is determined. Using this method, we study the diffusion process of the sucrose-water solution and report the diffusion coefficient with a reliable accuracy.


2020 ◽  
Vol 59 (25) ◽  
pp. 7712
Author(s):  
Rasoul Aalipour ◽  
Mohammad Taghi Tavassoly ◽  
Ahad Saber

Author(s):  
Y. Harada ◽  
T. Goto ◽  
H. Koike ◽  
T. Someya

Since phase contrasts of STEM images, that is, Fresnel diffraction fringes or lattice images, manifest themselves in field emission scanning microscopy, the mechanism for image formation in the STEM mode has been investigated and compared with that in CTEM mode, resulting in the theory of reciprocity. It reveals that contrast in STEM images exhibits the same properties as contrast in CTEM images. However, it appears that the validity of the reciprocity theory, especially on the details of phase contrast, has not yet been fully proven by the experiments. In this work, we shall investigate the phase contrast images obtained in both the STEM and CTEM modes of a field emission microscope (100kV), and evaluate the validity of the reciprocity theory by comparing the experimental results.


Author(s):  
R.A. Ploc

Samples of low-nickel Zircaloy-2 (material MLI-788-see(1)), when anodically polarized in neutral 5 wt% NaCl solutions, were found to be susceptible to pitting and stress corrosion cracking. The SEM revealed that pitting of stressed samples was occurring below a 2000Å thick surface film which behaved differently from normal zirconium dioxide in that it did not display interference colours. Since the initial film thickness was approximately 65Å, attempts were made to examine the product film by transmission electron microscopy to deduce composition and how the corrosion environment could penetrate the continuous layer.


Author(s):  
T.E. Pratt ◽  
R.W. Vook

(111) oriented thin monocrystalline Ni films have been prepared by vacuum evaporation and examined by transmission electron microscopy and electron diffraction. In high vacuum, at room temperature, a layer of NaCl was first evaporated onto a freshly air-cleaved muscovite substrate clamped to a copper block with attached heater and thermocouple. Then, at various substrate temperatures, with other parameters held within a narrow range, Ni was evaporated from a tungsten filament. It had been shown previously that similar procedures would yield monocrystalline films of CU, Ag, and Au.For the films examined with respect to temperature dependent effects, typical deposition parameters were: Ni film thickness, 500-800 A; Ni deposition rate, 10 A/sec.; residual pressure, 10-6 torr; NaCl film thickness, 250 A; and NaCl deposition rate, 10 A/sec. Some additional evaporations involved higher deposition rates and lower film thicknesses.Monocrystalline films were obtained with substrate temperatures above 500° C. Below 450° C, the films were polycrystalline with a strong (111) preferred orientation.


Sign in / Sign up

Export Citation Format

Share Document