Characterization of Amorphous Carbon Films Grown by Pulsed-laser Deposition

Characterization of Amorphous Carbon Films Grown by Pulsed-laser Deposition
Author:
Publisher:
Total Pages: 12
Release: 1998
Genre:
ISBN:

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Amorphous carbon (a-C) films grow via energetic processes such as pulsed-laser deposition (PLD). The cold-cathode electron emission properties of a-C are promising for flat-panel display and vacuum microelectronics technologies. These ultrahard films consist of a mixture of 3-fold and 4-fold coordinated carbon atoms, resulting in an amorphous material with diamond-like properties. The authors study the structures of a-C films grown at room temperature as a function of PLD energetics using x-ray reflectivity, Raman spectroscopy, high-resolution transmission electron microscopy, and Rutherford backscattering spectrometry. While an understanding of the electron emission mechanism in a-C films remains elusive, the onset of emission is typically preceded by conditioning where the material is stressed by an applied electric field. To simulate conditioning and assess its effect, the authors use the spatially-localized field and current of a scanning tunneling microscope tip. Scanning force microscopy shows that conditioning alters surface morphology and electronic structure. Spatially-resolved electron energy loss spectroscopy indicates that the predominant bonding configuration changes from predominantly 4-fold to 3-fold coordination.

Tetrahedrally Bonded Amorphous Carbon Films I

Tetrahedrally Bonded Amorphous Carbon Films I
Author: Bernd Schultrich
Publisher: Springer
Total Pages: 769
Release: 2018-03-10
Genre: Technology & Engineering
ISBN: 3662559277

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This book presents the status quo of the structure, preparation, properties and applications of tetrahedrally bonded amorphous carbon (ta-C) films and compares them with related film systems. Tetrahedrally bonded amorphous carbon films (ta-C) combine some of the outstanding properties of diamond with the versatility of amorphous materials. The book compares experimental results with the predictions of theoretical analyses, condensing them to practicable rules. It is strictly application oriented, emphasizing the exceptional potential of ta-C for tribological coatings of tools and components.

Diamond and Diamond-like Films and Coatings

Diamond and Diamond-like Films and Coatings
Author: Robert E. Clausing
Publisher: Springer Science & Business Media
Total Pages: 894
Release: 2012-12-06
Genre: Science
ISBN: 1468459678

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Diamond films grown by activated chemical vapor deposition have superlative thermal, mechanical, optical, and electronic properties combined with a very high degree of chemical inertness to most environments. These properties, together with the ability to fabricate films and shapes of considerable size, promise an exciting new material with many applications. Some applications are on the verge of commercialization but many await a few more technological developments. Diamond-like films are already employed in both commercial and military applications. The popular press, as well as the scientific and technological and industrial communities, are increasingly interested in the potential for future development of these materials. Although there are many technical papers and review articles published, there is no Single comprehensive introduction to these technologies. The Scientific Affairs Division of NATO recognized the need and the future importance of these technologies and authorized an Advanced Study Institute on diamond and diamond-like films. NATO Advanced Study Institutes are high level teaching activities at which a carefully defined subject is presented in a systematic and coherently structured program. The subject is treated in considerable depth by lecturers eminent in their fields and of international standing. The presentations are made to students who are scientists in the field or who possess an advanced general scientific background.

Energy Research Abstracts

Energy Research Abstracts
Author:
Publisher:
Total Pages: 586
Release: 1994
Genre: Power resources
ISBN:

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Semiannual, with semiannual and annual indexes. References to all scientific and technical literature coming from DOE, its laboratories, energy centers, and contractors. Includes all works deriving from DOE, other related government-sponsored information, and foreign nonnuclear information. Arranged under 39 categories, e.g., Biomedical sciences, basic studies; Biomedical sciences, applied studies; Health and safety; and Fusion energy. Entry gives bibliographical information and abstract. Corporate, author, subject, report number indexes.

Nanostructural Characterization of Amorphous Diamondlike Carbon Films

Nanostructural Characterization of Amorphous Diamondlike Carbon Films
Author:
Publisher:
Total Pages: 41
Release: 2000
Genre:
ISBN:

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Nanostructural characterization of amorphous diamondlike carbon (a-C) films grown on silicon using pulsed-laser deposition (PLD) is correlated to both growth energetic and film thickness. Raman spectroscopy and x-ray reflectivity probe both the topological nature of 3- and 4-fold coordinated carbon atom bonding and the topographical clustering of their distributions within a given film. In general, increasing the energetic of PLD growth results in films becoming more ''diamondlike'', i.e. increasing mass density and decreasing optical absorbance. However, these same properties decrease appreciably with thickness. The topology of carbon atom bonding is different for material near the substrate interface compared to material within the bulk portion of an a-C film. A simple model balancing the energy of residual stress and the free energies of resulting carbon topologies is proposed to provide an explanation of the evolution of topographical bonding clusters in a growing a-C film.

ETUDE DES COUCHES MINCES DE CARBONE PREPAREES PAR LA TECHNIQUE DE DEPOSITION PAR LASER PULSE

ETUDE DES COUCHES MINCES DE CARBONE PREPAREES PAR LA TECHNIQUE DE DEPOSITION PAR LASER PULSE
Author: XAVIER.. DIAZ
Publisher:
Total Pages: 152
Release: 1995
Genre:
ISBN:

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LE BUT DE CETTE THESE EST L'ETUDE DES PARAMETRES PHYSIQUES QUI FONT VARIER LES PROPRIETES ELECTRONIQUES ET MECANIQUES DES COUCHES MINCES DE CARBONE AMORPHE (A-C) EVAPOREES PAR LA TECHNIQUE DE DEPOSITION PAR LASER PULSE (PLD). TOUT D'ABORD, ON A FAIT DES EXPERIENCES POUR CONNAITRE LE SYSTEME EXPERIMENTAL: ON A ETUDIE LA COMPOSITION DU MATERIAU EVAPORE ET LA CINETIQUE DE DEPOSITION DES PARTICULES SUR LA SURFACE DE SI (111) 7X7. CETTE DERNIERE A ETE OBSERVE A L'ECHELLE ATOMIQUE AVEC UN MICROSCOPE A EFFET TUNNEL DANS L'ULTRA VIDE. DANS UNE DEUXIEME PARTIE, ON A CARACTERISE LES DEPOTS DE A-C. CES FILMS ONT UNE DENSITE ENTRE 2.45 G/CM#3 ET 2.8 G/CM#3 ET UNE DURETE JUSQU'A 50 GPA. ILS SONT SEMICONDUCTEURS AVEC UN GAP OPTIQUE DE 0.3 EV ET UNE RESISTIVITE ELECTRIQUE DE 10#5 CM. CES PROPRIETES SONT DEGRADEES SI L'ENERGIE CINETIQUE DES PARTICULES EVAPOREES EST DIMINUEE. L'ANALYSE PHYSICO-CHIMIQUE DE CES COUCHES MINCES A ETE FAITE EN UTILISANT LES SPECTROSCOPIES DE PHOTOEMISSION (XPS ET UPS), D'ABSORPTION DES RAYONS X (NEXAFS) ET RAMAN. CETTE ANALYSE REVELE QUE CES COUCHES SONT CONSTITUEES PAR DES ATOMES DE CARBONE HYBRIDES SP#2 ET SP#3. LA PROPORTION DES LIAISONS SP#3 PAR RAPPORT AUX LIAISONS SP#2 EST DE 40% POUR LES COUCHES DURES (45 GPA) ET 25% POUR LES MOINS DURES (22 GPA). LES RESULTATS NEXAFS OBTENUS EN DETECTION D'ELECTRON ET EN FLUORESCENCE SEMBLENT INDIQUER UN GRADIENT DE DENSITE DU MATERIAU, CELLE-CI AUGMENTANT DE LA SURFACE VERS LE VOLUME. FINALEMENT, LA SIMILITUDE OBSERVEE ENTRE LES SPECTRES RAMAN DE FILMS DE A-C AVEC DES DURETES SEMBLABLES MAIS DES GAP OPTIQUES RADICALEMENT DIFFERENTS INDIQUENT QUE LA SPECTROSCOPIE RAMAN EST PLUS SENSIBLE A L'ORGANISATION STRUCTURALE QU'AUX PROPRIETES ELECTRONIQUES DES DEPOTS DE A-C