Search results for "Microscope"
showing 10 items of 1412 documents
Reflection scanning microscopy.
1992
To image nontransparent samples we have utilized a special type of scanning-probe microscope that is referred to here as a reflection scanning microscope. The reflection scanning microscope provides a method for producing a scanned point light source as well as a system for collecting the light that is reflected by the sample. The system, which uses an optical fiber coupler, is easily installed on an existing photon scanning tunneling microscope. A calculation of the coupling coefficient between the natural propagation mode of the optical fiber and the light that is reflected by the sample is presented along with a comparison between calculated and measured values of the intensity of the li…
Imaging of surface plasmon propagation and edge interaction using a photon scanning tunneling microscope
1994
We report the direct imaging of surface plasmon propagation on thin silver films using the photon scanning tunneling microscope. It is found that the surface plasmon remains tightly confined in the original launch direction with insignificant scattering to other momentum states. A propagation length of 13.2 \ensuremath{\mu}m is measured at \ensuremath{\lambda}=632.8 nm. We also present images showing the interaction of a surface plasmon with the edge of the metal film supporting it. The most remarkable feature is the absence of specularly reflected beam.
Magnetic Domain Imaging with a Photoemission Microscope
1997
ABSTRACTPhotoelectron emission microscopy (PEEM) has proven to be a versatile analytical technique in surface science. When operated with circularly polarized light in the soft x-ray regime, however, photoemission microscopy offers a unique combination of magnetic and chemical information. Exploiting the high brilliance and circular polarization available at a helical undulator beamline, the lateral resolution in the imaging of magnetic domain structures may be pushed well into the sub-micrometer range. Using a newly designed photoemission microscope we show that under these circumstances not only domains, but also domain walls can be selectively investigated. The high sensitivity of the te…
A computer controlled patterning system for scanning probe microscopes
1999
Abstract A pattern generator system for lithography based on scanning force microscopes has been developed. Patterns to be miniaturized onto a chip can be scanned or drawn by any common graphical program. The pattern file is used to control a voltage simultaneously with the microscope probe scanning the surface of the substrate. The voltage can be used in numerous different ways to manipulate the substrate, depending on the lithographic method preferred. We have demonstrated the system by adding this voltage to the z -piezo voltage of the scanner, in order to make the probe plow the pattern into a film spinned on the sample. To maintain linearity in zooming in and rotating the scanning dire…
Enhanced photocatalytic performance of novel electrospun BN/TiO 2 composite nanofibers
2017
International audience; High activity boron nitride/titanium dioxide (BN/TiO2) composite nanofiber photocatalysts were synthesized for the first time via the electrospinning technique. The as-spun nanofibers with a controlled ratio of boron nitride nanosheets (BN) were calcined under air at 500 °C for 4 hours. Their morphological, structural and optical properties were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), BET surface area, Fourier-transform infrared (FTIR), Raman spectroscopy, UV-Visible spectrophotometry and room temperature photoluminescence (PL). The effect of loading different BN sheet amounts on the photocat…
XRMA analysis and X-ray diffraction analysis of dental enamel from human permanent teeth exposed to hydrogen peroxide of varying pH
2019
Background This in vitroinvestigation shows how 3.3% H2O2, at different pH-values affects the enamel. Material and Methods A number of fifteen human premolars were used. The enamel of the coronal half in six of the teeth, were exposed by H2O2. Nine teeth were prepared to enamel powder. The enamel was exposed to 3.3% H2O2, at six different pH-values (pH range 4.5 - 7.0). Analyses of the topography of enamel performed by scanning electron microscope (SEM) and the chemical composition of enamel by X-ray microanalysis (XRMA). X-ray powder diffraction (XRD) analysed the crystallinity in enamel powder. Results The exposure to H2O2 at pH5.5 resulted in a decrease of O in the exposed enamel, and ch…
Growth and characterisation of MnTe crystals
2001
We report on the low temperature growth of MnTe crystals by means of travelling solution methods. Two different processes are considered; a classical THM process using a low temperature presynthesised MnTe ingot, and a modified THM process, in which an increasing length of solvent zone collects the tellurium that was added to the stoichiometric charge to decrease the reaction temperature. Ingots from the two methods are analysed by means of scanning electron microscopy, X-ray diffractometry, resistivity, susceptibility and optical absorption measurements.
Studies on atomic layer deposition of IRMOF-8 thin films
2015
Deposition of IRMOF-8 thin films by atomic layer deposition was studied at 260–320 C. Zinc acetate and 2,6-naphthalenedicarboxylic acid were used as the precursors. The as-deposited amorphous films were crystallized in 70% relative humidity at room temperature resulting in an unknown phase with a large unit cell. An autoclave with dimethylformamide as the solvent was used to recrystallize the films into IRMOF-8 as confirmed by grazing incidence x-ray diffraction. The films were further characterized by high temperature x-ray diffraction (HTXRD), field emission scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), time-of-flight elastic recoil detection analysis (TOF-…
Optical and structural studies of GaN 3D structures selectively grown by MOCVD
2004
Abstract This paper presents preliminary results on the selective growth of three-dimensional (3D) micrometric metallic structures by the MOCVD technique. The 3D structure growth occurs by simply feeding the reactor gas phase with a conventional flow of metal-organic (MO), trimethyl-gallium (TMGa) molecules. Selectivity occurs at the substrate surface in which MO species travel tens of micrometers in order to build up the 3D structure. After the growth, these structures are nitrided in order to give GaN-related optical visible emission. Optical emission results are presented and discussed in this paper. Both 3D structures deposition and annealing experiments can be extended to other III–V m…
A new approach to the crystal growth of Hg1−xMnxTe by the cold travelling heater method (CTHM)
2001
Abstract In order to obtain crystals with a homogeneous composition and to reduce the Hg high pressure related to the temperature synthesis reaction between the components in elemental form, Hg 1− x Mn x Te bulk crystals were produced by the cold travelling heater method (CTHM). Following the technique initially proposed for the growth of CdHgTe by the Triboulet group, the feed material was a split ingot of two segments, one of HgTe and the other of MnTe, with cross-sectional areas chosen to establish the desired final composition. The growth was carried out at a temperature of 600°C and a rate of 2 mm/h. The Hg 1− x Mn x Te crystals have been characterised by scanning electron microscopy, …