Chemical structure of diamond-like carbon thin films

Author(s):  
N.-H. Cho ◽  
K.M. Krishnan ◽  
D.B. Bogy

Diamond-like carbon (DLC) films have attracted much attention due to their useful properties and applications. These properties are quite variable depending on film preparation techniques and conditions, DLC is a metastable state formed from highly non-equilibrium phases during the condensation of ionized particles. The nature of the films is therefore strongly dependent on their particular chemical structures. In this study, electron energy loss spectroscopy (EELS) was used to investigate how the chemical bonding configurations of DLC films vary as a function of sputtering power densities. The electrical resistivity of the films was determined, and related to their chemical structure.DLC films with a thickness of about 300Å were prepared at 0.1, 1.1, 2.1, and 10.0 watts/cm2, respectively, on NaCl substrates by d.c. magnetron sputtering. EEL spectra were obtained from diamond, graphite, and the films using a JEOL 200 CX electron microscope operating at 200 kV. A Gatan parallel EEL spectrometer and a Kevex data aquisition system were used to analyze the energy distribution of transmitted electrons. The electrical resistivity of the films was measured by the four point probe method.

1990 ◽  
Vol 5 (11) ◽  
pp. 2543-2554 ◽  
Author(s):  
N-H. Cho ◽  
K. M. Krishnan ◽  
D. K. Veirs ◽  
M. D. Rubin ◽  
C. B. Hopper ◽  
...  

Thin films of amorphous carbon (a–C) and amorphous hydrogenated carbon (a–C:H) were prepared using magnetron sputtering of a graphite target. The chemical structures of the films were characterized using electron energy loss spectroscopy (EELS) and Raman spectroscopy. The mass density, hardness, residual stress, optical band gap, and electrical resistivity were determined, and their relation to the film's chemical structure are discussed. It was found that the graphitic component increases with increasing sputtering power density. This is accompanied by a decrease in the electrical resistivity, optical band gap, mass density, and hardness. Increasing the hydrogen content in the sputtering gas mixture results in decreasing hardness (14 GPa to 3 GPa) and mass density, and increasing optical band gap and electrical resistivity. The variation in the physical properties and chemical structures of these films can be explained in terms of the changes in the volume of sp2-bonded clusters in the a–C films and changes in the termination of the graphitic clusters and sp3-bonded networks by hydrogen in the a–C:H films.


1989 ◽  
Vol 164 ◽  
Author(s):  
N.-H. Cho ◽  
K.M. Krishnan ◽  
D.K. Veirs ◽  
M.D. Rubin ◽  
C.B. Hopper ◽  
...  

AbstractThin films of diamond-like amorphous carbon were prepared by dc magnetron sputtering. A systematic variation in the physical properties of the films (mass density and electrical resistivity) was found as a function of sputtering power density. Chemical bonding and microstructure of the carbon thin films were investigated using electron energy loss spectroscopy (EELS) and Raman spectroscopy. Films grown at a lower power density were found to have more sp3 -bonded atomic sites and larger graphite microcrystals than films produced at higher sputtering power densities.


Author(s):  
J. Kulik ◽  
Y. Lifshitz ◽  
G.D. Lempert ◽  
S. Rotter ◽  
J.W. Rabalais ◽  
...  

Carbon thin films with diamond-like properties have generated significant interest in condensed matter science in recent years. Their extreme hardness combined with insulating electronic characteristics and high thermal conductivity make them attractive for a variety of uses including abrasion resistant coatings and applications in electronic devices. Understanding the growth and structure of such films is therefore of technological interest as well as a goal of basic physics and chemistry research. Recent investigations have demonstrated the usefulness of energetic ion beam deposition in the preparation of such films. We have begun an electron microscopy investigation into the microstructure and electron energy loss spectra of diamond like carbon thin films prepared by energetic ion beam deposition.The carbon films were deposited using the MEIRA ion beam facility at the Soreq Nuclear Research Center in Yavne, Israel. Mass selected C+ beams in the range 50 to 300 eV were directed onto Si {100} which had been etched with HF prior to deposition.


2020 ◽  
Vol 23 (1) ◽  
pp. 65-77 ◽  
Author(s):  
Mohammad Musarraf Hussain

Erythrina is a significant source of phytoconstituents. The aim of this review is to solicitude of classification, synthesis, and phytochemicals with biological activities of Erythrina. In our previous review on this genus (Hussain et. al., 2016a) fifteen species (Erythrina addisoniae, E. caribeae, E. indica, E. lattisima, E. melanacantha, E. mildbraedii, E. poeppigiama, E. stricta, E. subumbrans, E. veriagata, E. vespertilio, E. velutina, E. zeberi, E. zeyheri and E. americana) have been studied and 155 molecules with chemical structures were reported. A further comprehensive review was done upon continuation on the same genus and thirteen species (E. abyssinica, E. arborescens, E. berteroana, E. burttii, E. caffra, E. coralloids, E. crista-galli, E. fusca, E. herbaceae, E. lysistemon, E. mulungu, E. speciosa and E. tahitensis) of Erythrina have been studied and 127 compounds are reported as phytoconstituents with their chemical structure in this review. Erythrina crista-galli and E. lysistemon consist of highest number of chemical constituents. Bangladesh Pharmaceutical Journal 23(1): 65-77, 2020


Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1293
Author(s):  
Chih-Hui Yang ◽  
Keng-Shiang Huang ◽  
Yi-Ting Wang ◽  
Jei-Fu Shaw

Generally, bacteriochlorophyllides were responsible for the photosynthesis in bacteria. Seven types of bacteriochlorophyllides have been disclosed. Bacteriochlorophyllides a/b/g could be synthesized from divinyl chlorophyllide a. The other bacteriochlorophyllides c/d/e/f could be synthesized from chlorophyllide a. The chemical structure and synthetic route of bacteriochlorophyllides were summarized in this review. Furthermore, the potential applications of bacteriochlorophyllides in photosensitizers, immunosensors, influence on bacteriochlorophyll aggregation, dye-sensitized solar cell, heme synthesis and for light energy harvesting simulation were discussed.


Author(s):  
O. N. Opanasenko ◽  
N. P. Krutko ◽  
O. L. Zhigalova ◽  
O. V. Luksha

Interfacial interactions of cationic surfactants of various chemical structures at the solution / finely dispersed mineral material (quartz and dolomite) interface were studied. It is established that the modification of the surfaces of quartz and dolomite with cationic surfactants leads to a change in the structure and radius of the capillaries due to the formation of adsorption-solvate shells. The hydrophobic ability of cationic surfactants is determined by the structure of the hydrophilic part of their molecules – the balance of amino groups in the alkyl chains and the absence of steric hindrances during adsorption interaction with the surface of mineral materials. The mixture of surfactants containing six amino groups and a polyhydric alcohol glycerin has an effective hydrophobic ability from both aqueous and highly mineralized solutions.


METANA ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 33-38
Author(s):  
Paryanto Paryanto ◽  
Sunu Herwi Pranolo ◽  
Ari Diana Susanti ◽  
Kristina Ratna Dewi ◽  
Meydiana Rossari

Textile dyes are divided into two types, natural dyes and synthetic dyes. Natural dyes commonly made from extraction. Extraction is a process in which one or more components are separated selectively from a liquid or solid mixture, the feed, by means of a liquid immiscible solvent. Extraction can be classified into two group, liquid extraction and solid-liquid extraction. Solvents that are usually used in the extraction of natural dyes are aquades and ethanol. The purpose of this research was to determine the chemical structure, especially tannin in natural dyes from mangrove species Rhizophora stylosa through several samples testing natural dyes. Rhizophora stylosa that have been extracted and evaporated will conducted several tests to obtain chemical structures in natural dyes and yield of tannin in natural dyes. Tests carried out include testing FT-IR, and HPLC. Based on FT-IR analysis, the extraction of Rhizophora stylosa containing tannin indicated by the presence of hydroxyl (O-H) in the area of 3385.36 cm-1, aromatic (C-H) in the area of 1365.53 cm-1, carbonyl (C=O) in the area 1646.36 cm-1, esters (C-O) in the area 1217.30 cm-1. While tannin content obtained from the analysis of HPLC were 6.087 ppm. 


Coatings ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 54 ◽  
Author(s):  
Ruriko Hatada ◽  
Stefan Flege ◽  
Wolfgang Ensinger ◽  
Sabine Hesse ◽  
Shuji Tanabe ◽  
...  

The intrinsic high electrical resistivity of diamond-like carbon (DLC) films prevents their use in certain applications. The addition of metal or nitrogen during the preparation of the DLC films leads to a lower resistivity of the films, but it is usually accompanied by several disadvantages, such as a potential contamination risk for surfaces in contact with the film, a limited area that can be coated, deteriorated mechanical properties or low deposition rates of the films. To avoid these problems, DLC films have been prepared by plasma source ion implantation using aniline as a precursor gas, either in pure form or mixed with acetylene. The nitrogen from the precursor aniline is incorporated into the DLC films, leading to a reduced electrical resistivity. Film properties such as hardness, surface roughness and friction coefficient are nearly unchanged as compared to an additionally prepared reference sample, which was deposited using only pure acetylene as precursor gas.


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