Drifts surface characterization of Zincblende nanostructured GaN

1997 ◽  
Vol 501 ◽  
Author(s):  
Kenneth E. Gonsalves ◽  
Greg Carlson ◽  
Marie-Isabelle Baraton
Keyword(s):  
Polymer Nanocomposites ◽  
Surface Characterization ◽  
Diffuse Reflectance ◽  
Chemical Species ◽  
Atomic Layer ◽  
Surface Chemical ◽  
Nanosized Powder ◽  
Fourier Transform Spectrometry ◽  
Diffuse Reflectance Infrared

ABSTRACTThe use of GaN/polymer nanocomposites in optoelectronics requires a perfect control of the GaN dispersion in the polymer matrix. This cannot be achieved without a good knowledge of the first atomic layer of the GaN nanoparticles. This paper reports the characterization of the surface chemical species of a GaN nanosized powder by diffuse reflectance infrared Fourier transform spectrometry.

Study of the dehydroxylation of kaolinite and alunite from a Mexican clay with DRIFTS-MS

Clay Minerals ◽  
2016 ◽  
Vol 51 (1) ◽  
pp. 55-68 ◽  
Author(s):  
N.R. Osornio-Rubio ◽  
J.A. Torres-Ochoa ◽  
M.L. Palma-Tirado ◽  
H. Jiménez-Islas ◽  
R. Rosas-Cedillo ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Hydroxyl Groups ◽  
Mineralogical Characterization ◽  
Fourier Transform Spectrometry ◽  
Stretching Vibration ◽  
Kaolinitic Clay ◽  
Diffuse Reflectance Infrared ◽  
Refractory Bricks

AbstractFew reports exist on the use of Diffuse Reflectance Infrared Fourier Transform Spectrometry coupled with Mass Spectrometry (DRIFTS-MS) in situ to monitor the dehydroxylation of kaolinitic clays. The use of DRIFTS-MS in situ allows study of the effect of heat treatment on the dehydroxylation, identifying intensities and temperatures at which the hydroxyl groups are released, forming metakaolinite and meta-alunite. The effluent gases from the infrared cell were analysed by mass spectrometry. The decrease in intensity of the bands at 3694, 3669, 3650 and 3621 cm−1 associated with the −OH stretching vibration modes of AlVI−OH−AlVI of kaolinite began at 450°C. Two additional bands at 3513 and 3485 cm−1 are associated with the vibration of AlVI−OH of alunite that also began to disappear during thermal treatment. Monitoring of the fractions m/e 17 and 18 using a mass spectrometer revealed that the intensity of these fractions increased starting at 450°C. Therefore, it is possible to study the dehydroxylation process of clays during thermal treatment.Chemical and mineralogical characterization of a kaolinitic clay (KN) fromMexico showed that the clay consists of 64.8% kaolinite, 11.0% alunite and 24.4% quartz based on PXRD, EDS, TG/DTA, TEM and FTIR results, and suggested that the material might have potential for use in the manufacture of ceramics, refractory bricks or geopolymers.

Characterization of Surface Contaminants by a Silver Film-Enhanced IR—Johnson Method

1997 ◽  
Vol 51 (10) ◽  
pp. 1460-1463 ◽  
Author(s):  
Nobuaki Marino ◽  
Kiichirou Murai ◽  
Yoshinori Kataora
Keyword(s):  
Polymer Film ◽  
Silicon Wafer ◽  
Photoelectron Spectroscopy ◽  
Present Method ◽  
Surface Characterization ◽  
Diffuse Reflectance ◽  
Silver Film ◽  
Wafer Surface ◽  
Surface Contaminants

Characterization of nanometer-order organic contaminants on polymer film and silicon wafer surface has been investigated by a modified IR–Johnson method. We have proposed a silver film-enhanced IR–Johnson method that is useful for surface contaminant analysis. In the present method, organic traces are transferred from the surface of a polymer film or silicon wafer onto the KBr particles deposited with silver film, and then the KBr particles are analyzed directly by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Infrared absorption of organic traces was enhanced by the presence of silver island film. With this method, a spectrum of nanometer-order organic traces can be obtained without any interference from the polymer film substrate. The present method is as surface-sensitive as X-ray photoelectron spectroscopy (XPS) and provides a large amount of information on the chemical structure of surface contaminants. This is a promising method for the surface characterization of polymer films and silicon wafer. Index Headings: Infrared; Diffuse reflectance; Surface enhancement.

Diffuse Reflectance Infrared Spectroscopic Characterization of Silica Dehydroxylation

1990 ◽  
Vol 44 (1) ◽  
pp. 69-75 ◽  
Author(s):  
Robert L. White ◽  
Aurobindo Nair
Keyword(s):  
Force Constant ◽  
Diffuse Reflectance ◽  
Spectroscopic Characterization ◽  
Absorption Bands ◽  
Stretching Vibration ◽  
Diffuse Reflectance Infrared ◽  
Highly Strained ◽  
Infrared Absorption Bands ◽  
Absorbance Band

Diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS) is employed to study the dehydroxylation of amorphous silica. Dehydroxylation results in the appearance of infrared absorption bands at 1022, 1107, and 1240 cm−1 assigned to asymmetric stretching vibrations for three different siloxane bridge types. The 1107-cm−1 absorbance band represents a siloxane bridge that is indistinguishable from bulk species. The 1022-cm−1 absorbance band represents a siloxane bridge with a bond angle that is smaller than the bulk, with little change in the stretching vibration force constant. The 1240-cm−1 absorbance band derives from a siloxane bridge characterized by a stretching force constant significantly larger than that of bulk siloxane bridges. This band may be indicative of a highly strained or broken siloxane bridge.

Determination of Silicon Dioxide in Silicon Carbide by Diffuse Reflectance Infrared Fourier Transform Spectrometry

1986 ◽  
Vol 40 (3) ◽  
pp. 310-313 ◽  
Author(s):  
Akira Tsuge ◽  
Yoshinori Uwamino ◽  
Toshio Ishizuka
Keyword(s):  
Fourier Transform ◽  
Silicon Dioxide ◽  
Diffuse Reflectance ◽  
Peak Height ◽  
Particle Sizes ◽  
Fourier Transform Spectrometry ◽  
Peak Intensity ◽  
Analytical Curve ◽  
Diffuse Reflectance Infrared

Diffuse reflectance infrared Fourier transform spectrometry was applied to the determination of SiO2 in SiC powders. The main peaks of SiO2 were observed in the 1000–1250 cm−1 region. The peak intensities were estimated from the peak height at 1150 cm−1. The intensities were little affected by the particle sizes of SiC powders in the 1–9–μm region. The linear relationship between peak intensity and concentration was obtained in the concentration range of 0–5 wt% SiO2. The analytical curve was successfully used for the determination of SiO2 in a few commercial SiC powders.

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