Atomic structure and physical properties of amorphous carbon and its hydrogenated analogs

Frauenheim, Thomas; Blaudeck, P.; Stephan, U.; Jungnickel, G.

doi:10.1103/physrevb.48.4823

Cited by 133 publications

(34 citation statements)

References 46 publications

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“…Depending on preparation conditions and hydrogen concentration a-C:H materials can vary from soft, low-density phases with polymer-like atomic structures to hard, diamond-like materials with a high content of C-C sp 3 bonds. Even though a-C:H films have important practical applications due to their diverse properties [20] there has been only a handful of theoretical studies of these systems [47][48][49][50]. Moreover, due to computational costs all these attempts have been restricted to small system sizes and rather unrealistic conditions and are therefore of limited practical use.…”

Section: From A-c To A-c:hmentioning

confidence: 98%

Atomistic modeling of hydrocarbon systems using analytic bond-order potentials

Mrovec

Moseler

Elsässer

et al. 2007

Progress in Materials Science

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Section: From A-c To A-c:hmentioning

confidence: 98%

Atomistic modeling of hydrocarbon systems using analytic bond-order potentials

Mrovec

Moseler

Elsässer

et al. 2007

Progress in Materials Science

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“…Later, total energy calculations by Frauenheim et al [4] found that the sp 2 sites formed much smaller clusters, and these tended to be olefinic chain-like groups rather than aromatic. Recently, it was found that the Raman spectrum gave direct information on the sp 2 configuration [5].…”

mentioning

confidence: 99%

Defects in Diamond-Like Carbon

Robertson

2001

phys. stat. sol. (a)

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The nature and role of electronic defects in amorphous diamond-like carbons (DLC) is described. The defect has recently been shown by electron spin resonance to be an unpaired spin on a small sp 2 -bonded cluster. The defect density is large in DLC so defect states form continuous distribution of states with tail states. Defects and tail states can act as non-radiative recombination centres to quench photoluminescence, depending on the position of the demarcation levels.

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“…Possible forms of a-C are represented by the ternary phase diagram of a-C growth in Fig. 15 [13,60]. …”

Section: Forms Of Amorphous Carbonmentioning

confidence: 99%

Synthesis of Carbon-based and Metal-Oxide Thin Films using High Power Impulse Magnetron Sputtering

Aijaz¹

2014

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The work presented in this thesis deals with synthesis of carbon-based as well as metaloxide thin films using highly ionized plasmas. The principal deposition method employed was high power impulse magnetron sputtering (HiPIMS). The investigations on plasma chemistry, plasma energetics, plasma-film interactions and its correlation to film growth and resulting film properties were made. The thesis is divided into two parts: (i) HiPIMSbased deposition of carbon-based thin films and (ii) HiPIMS-based deposition of metaloxide thin films.In the first part of the thesis, HiPIMS based strategies are presented that were developed to address the fundamental issues of low degree of carbon ionization and low deposition rates of carbon film growth in magnetron sputtering. In the first study, a new strategy was introduced for increasing the degree of ionization of sputtered carbon via increasing the electron temperature in the discharge by using a higher ionization potential buffer gas (Ne) in place of commonly used Ar. A direct consequence of enhanced electron temperatures was observed in the form of measured large fluxes of ionized carbon at the substrate position. Consequently, high mass densities of the resulting amorphous carbon (a-C) thin films reaching 2.8 g/cm 3 were obtained.In another study, feasibility of HiPIMS-based high density discharges for high-rate synthesis of dense and hard a-C thin films was explored. A strategy was compiled and implemented that entailed coupling a hydrocarbon precursor gas (C 2 H 2 ) with high density discharges generated by the superposition of HiPIMS and direct current magnetron sputtering (DCMS). Appropriate control of discharge density (by tuning HiPIMS/DCMS power ratio), gas phase composition and energy of the ionized depositing species lead to a route capable of providing ten-fold increase in the deposition rate of a-C film growth compared to that obtained using HiPIMS Ar discharge in the first study. The increased deposition rate was achieved without significant incorporation of H (<10 %) and with relatively high hardness (>25 GPa) and mass density (~2.32 g/cm 3 ). The knowledge gained in this work was utilized in a subsequent work where the feasibility of adding high II ionization potential buffer gas (Ne) to increase the electron temperature in an Ar/C 2 H 2 HiPIMS discharge was explored. It was found that the increased electron temperature lead to enhanced dissociation of hydrocarbon precursor and an increased H incorporation into the growing film. The resulting a-C thin films exhibited high hardness (~ 25 GPa), mass densities in the order of 2.2 g/cm 3 and H content as low as about 11%. The striking feature of the resulting films was low stress levels where the films exhibited compressive stresses in the order of 100 MPa.In the second part of the thesis, investigations on reactive HiPIMS discharge characteristics were made for technologically relevant metal-oxide systems. In the first study, the discharge characteristics of Ti-O and Al-O were investigated by studying ...

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Atomic structure and physical properties of amorphous carbon and its hydrogenated analogs

Cited by 133 publications

References 46 publications

Atomistic modeling of hydrocarbon systems using analytic bond-order potentials

Atomistic modeling of hydrocarbon systems using analytic bond-order potentials

Defects in Diamond-Like Carbon

Synthesis of Carbon-based and Metal-Oxide Thin Films using High Power Impulse Magnetron Sputtering

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