Physical Properties of Thin Films of GaAs and AlxGa1-xAs Grown by Solid-Arsenic-Based MOCVD

2014 ◽  
Vol 976 ◽  
pp. 25-29
Author(s):  
Roberto Castillo-Ojeda ◽  
Joel Diaz-Reyes ◽  
Miguel Galván-Arellano ◽  
Ramon Peña-Sierra
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Low Temperature ◽  
Growth Process ◽  
Carbon Incorporation ◽  
Infrared Measurements ◽  
Hall Effect Measurements ◽  
Low Temperature Photoluminescence

We have studied the optical properties of GaAs and AlxGa1-xAs thin films using low-temperature photoluminescence and Fourier transform infrared spectroscopy. The GaAs and its alloys were grown by MOCVD using solid arsenic instead of arsine, as the arsenic precursor. The gallium and aluminium precursors were trimethylgallium (TMGa) and trimethylaluminium (TMAl), respectively. Some difficulties for growing AlxGa1-xAs by solid-arsenic-based MOCVD system are the composition homogeneity of the layers and the oxygen and carbon incorporation during the growth process. The composition homogeneity of the films was evaluated by low-temperature photoluminescence. Infrared measurements on the samples allowed the identification of the residual impurities, which are carbon-substitutional, Ga2O3, molecular oxygen, humidity and two unidentified impurities. Samples grown at temperatures lower than 750°C were highly resistive, independently of the ratio V/III used; the samples grown at higher temperatures were n-type, as it was proved by Hall effect measurements.

scholarly journals Study on Performance Damage and Mechanism Analysis of Asphalt under Action of Chloride Salt Erosion

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3089
Author(s):  
Peilei Zhou ◽  
Wensheng Wang ◽  
Lili Zhu ◽  
Haoyun Wang ◽  
Yongming Ai
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
High Temperature ◽  
Low Temperature ◽  
Temperature Sensitivity ◽  
Salt Solution ◽  
Solution Concentration ◽  
Chloride Salt ◽  
Temperature Performance ◽  
Low Temperature Performance

This study aims to investigate the performance evolution and mechanism of asphalt under action of chloride salt erosion. Asphalt samples soaked with five different snow melting chloride salt concentrations were taken as the research object. Then, the high-temperature performance, low-temperature performance, temperature sensitivity and asphalt–aggregate adhesion property of asphalt samples were carried out. Additionally, Fourier transform infrared spectroscopy (FTIR) was used to explore the mechanism of chloride salt erosion on asphalt. Test results showed the linear variation relationships of high-temperature performance, low-temperature performance and temperature sensitivity with chloride salt concentrations. The high-temperature performance of asphalt would be improved by chloride snowmelt salt. With the increase in the chloride salt solution concentration, the low-temperature performance of asphalt became worse, and the temperature sensitivity increased. Moreover, after the effect of the chloride salt solution, the asphalt–aggregate adhesion property decreased with the increase in the chloride salt solution concentration. It is necessary to control the amount of chloride snowmelt salt in the actual snow removal projects. Finally, based on Fourier transform infrared spectroscopy, the mechanism of chloride salt erosion on asphalt was preliminarily explored. With the increase in the chloride salt solution concentration, the proportion of light components (saturated fraction, aromatic fraction) in asphalt decreased, and the proportion of heavy components (resin and asphaltene) with good thermal stability increased.

Low Temperature Evaluation of Carbon and Oxygen Contaminants in Silicon

1980 ◽  
Vol 34 (2) ◽  
pp. 171-173 ◽  
Author(s):  
D. G. Mead
Keyword(s):  
Fourier Transform ◽  
Low Temperature ◽  
Room Temperature ◽  
Fourier Transform Infrared ◽  
Spectral Subtraction ◽  
Atomic Carbon ◽  
Infrared Measurements ◽  
Oxygen Concentrations

Low temperature Fourier transform infrared measurements at 20 K on some wafers containing substitutional atomic carbon and oxygen are presented. Spectral subtraction techniques at 20 K indicate an increase of approximately 5 times in sensitivity compared to the room temperature evaluation of the carbon and oxygen concentrations.

Optical Investigation of 3C-SiC Hetero-Epitaxial Layers Grown by Sublimation Epitaxy under Gas Atmosphere

2014 ◽  
Vol 778-780 ◽  
pp. 243-246
Author(s):  
P. Kwasnicki ◽  
V. Jokubavicius ◽  
J.W. Sun ◽  
H. Peyre ◽  
R. Yakimova ◽  
...  
Keyword(s):  
Low Temperature ◽  
Growth Process ◽  
Epitaxial Layers ◽  
Optical Investigation ◽  
Defect Sites ◽  
Vacuum Atmosphere ◽  
Gas Atmosphere ◽  
Low Temperature Photoluminescence

We investigated three 3C-SiC samples grown on 6H SiC substrate by sublimation epitaxy under gas atmosphere. We focus on the low temperature photoluminescence and Raman measurements to show that compare to a growth process under vacuum atmosphere, the gas atmosphere favor the incorporation of impurities at already existing and/or newly created defect sites.

Explosive Thermal Decomposition Mechanism of NTO

1995 ◽  
Vol 418 ◽  
Author(s):  
David J. Beardall ◽  
Tod R. Botcher ◽  
Charles A. Wight
Keyword(s):  
Thin Films ◽  
Thermal Decomposition ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Condensed Phase ◽  
Decomposition Product ◽  
Rapid Heating ◽  
Initial Step ◽  
Thermal Decomposition Mechanism ◽  
Decomposition Products

AbstractThe initial step of the thermal decomposition of NTO (5-nitro-2,4-dihydro-3H-1,2,4- triazol-3-one) is determined by pulsed infrared laser pyrolysis of thin films. Rapid heating of the film and quenching to 77 K allows one to trap the initial decomposition products in the condensed phase and analyze them using transmission Fourier-transform infrared spectroscopy. The initial decomposition product is CO2; NO2 and HONO are not observed. We propose a new mechanism for NTO decomposition in which CO2 is formed.

Dehydrogenation and Polymerization of TiOxHy Films in Obtaining Anatase Coating at Low Temperature

2002 ◽  
Vol 749 ◽  
Author(s):  
Kouichi Takayama ◽  
Shigeo Ohshio ◽  
Hidetoshi Saitoh
Keyword(s):  
Raman Spectroscopy ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Low Temperature ◽  
Vapor Deposition ◽  
Crystal Size ◽  
Chemical Vapor ◽  
Amorphous Films ◽  
X Ray ◽  
Titanium Tetra Isopropoxide

ABSTRACTChemical-vapor-deposition of titanium tetra-isopropoxide (TTIP) under the atmosphere at low temperature has been conducted. The structure of the obtained films was assessed using Fourier transform infrared spectroscopy, X-ray diffractometry and Raman spectroscopy. These analyses indicated that amorphous TiOxHy films were obtained at gas temperatures in the range of 150–300 °C, and crystalline anatase-TiO2 film was formed at 350 °C. This distinction is accounted for by plausible chemical reactions as follows; the hydroxyl reaction of TTIP below 350 °C promotes the formation of the amorphous TiOxHy. As the temperature goes up to 350 °C, dehydrogenation of the TiOxHy films promotes to form crystalline TiO2. Also the obtained amorphous films were annealed for 10 min under the atmosphere in assessing the transformation proceeding in the solid state. The structural change is shown at 350 °C, indicating that the crystalline phase would be formed via dehydrogenation and polymerization on the surface of the amorphous phase under the atmosphere. The crystal size of the annealed films was evaluated in assessment for the transformation.

Low-Temperature Growth of Nanocrystalline Mn-Doped ZnS Thin Films Prepared by Chemical Bath Deposition and Optical Properties

2009 ◽  
Vol 21 (12) ◽  
pp. 2375-2385 ◽  
Author(s):  
Alireza Goudarzi ◽  
Ghaffar Motedayen Aval ◽  
Sung Soo Park ◽  
Myeon-Cheon Choi ◽  
Reza Sahraei ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Low Temperature ◽  
Chemical Bath Deposition ◽  
Temperature Growth ◽  
Low Temperature Growth ◽  
Mn Doped
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