David Britz - Academia.edu (original) (raw)
Papers by David Britz
Corrosion resistance is a critical property for semiconductor processing chamber components. Corr... more Corrosion resistance is a critical property for semiconductor processing chamber components. Corrosive plasmas are omnipresent is semiconductor deposition processes, including plasma enhanced chemical vapor deposition (PECVD), physical vapor deposition (PVD), and etching. Process chamber cleanliness during plasma processing is becoming increasingly important as device feature sizes shrink. Particles that originate from erosion of the chamber components can lead to device yield losses, and eventually will result in the process chamber requiring the replacement of chamber components that are exposed to such plasmas. Thus the chamber components coatings are critical for tool performance and uptime.
AIP Conference Proceedings, 2004
Carbon nanotubes can encapsulate several molecular species forming one-dimensional crystals. Usin... more Carbon nanotubes can encapsulate several molecular species forming one-dimensional crystals. Using previously reported methods we produced directly-bonded, asymmetric C60-C70 dimers and oxygen-bridged dimers of the type C60-O-C60. We present here microscopic evidence of filling single-walled carbon nanotubes (SWNTs) with the above fullerene dimers. The most important filling constraint is found to be the nanotube size. SWNTs with diameters around 1.6
Physical Review B, 2007
We report on a complete characterization of the optical dispersion properties of conducting thin ... more We report on a complete characterization of the optical dispersion properties of conducting thin films of single-wall carbon nanotubes ͑SWCNTs͒. The films studied exhibit sheet resistances between 50 and 1000 ⍀ / sq and optical transparencies between 65% and 95% on glass and quartz substrates. These films have the potential to replace transparent conducting oxides in applications such as photovoltaics and flat-panel displays; however, their optical properties are not sufficiently well understood. The SWCNT films are shown to be hole conductors, potentially enabling their use as hole-selective contacts and allowing alternative device designs. The fundamental optical, morphological, and electrical characteristics of the films are presented here, and a phenomenological optical model that accurately describes the optical behavior of the films is introduced. Particular attention is paid to ellipsometry measurements and thorough evaluation of the reflection and absorption spectra of the films.
Physical Review Letters, 2004
We have assembled molecular arrays of C 60 inside double-walled carbon nanotubes (DWNTs) with int... more We have assembled molecular arrays of C 60 inside double-walled carbon nanotubes (DWNTs) with internal diameters of 11-26 Å and directly observed the existence of different crystalline phases of C 60 previously predicted theoretically. The structure of the encapsulated C 60 crystal is defined by the internal diameter of the DWNT, as the molecules adjust their packing arrangement in order to maximize van der Waals interactions. We have also shown that fullerenes in C 60 @DWNT interact with the outer layer of DWNTs, as demonstrated by the efficient filling of DWNTs with internal diameters of less than 12 Å .
Spherical carbon cages of fullerene molecules interact by van der Waals forces to form close-pack... more Spherical carbon cages of fullerene molecules interact by van der Waals forces to form close-packed arrangements in the solid state, such as the face-centered cubic lattice formed by C60 at room temperature. [1] Owing to the low directionality and low energy of the interfullerene interactions neutral fullerene molecules (such as C60) are freely rotating in the crystal at room temperature. Contrasting to the empty fullerene cages, metal-containing endohedral fullerenes are known to have large electric dipole moments of 3–4 Debye. Therefore, it should be expected that intermolecular interactions in the solid M@Cn, (M=metal center) are dominated by strong dipolar interactions. For example, fullerene Ce@C82 has a large dipole moment owing to the transfer of three valence electrons from the Ce atom to C82 cage. [4] This fullerene crystallizes in a hexagonal or a face-centered cubic close pack arrangement. However, despite the dipole moment the fullerene Ce@C82 has been shown to retain it...
Aps Meeting Abstracts, 2004
ABSTRACT Using density functional theory calculations, the electronic structure of fullerene dime... more ABSTRACT Using density functional theory calculations, the electronic structure of fullerene dimers have been investigated which would be useful for quantum computing. We have studied two directly linked fullerenes forming a bridging ring (C60-C60 and C70-C60), and two fullerenes linked with additional bridging oxygen atom between them (C60-O-C60 and C70-O-C60). We have also identified the new geometry of C70-C-C60 which has a carbon bridging atom with four bonds to two fullerenes. The structural properties and electronic structures of each dimers have investigated theoretically, and compared to experimental observations. The numbers of stable isomers in each kind of dimers and relative stability of dimers have in good agreement with experimental results. We have also calculated doubly charged dimers in order to predict the applicability to quantum computing.
Journal of Physical Chemistry C, 2007
Thin films of single-wall carbon nanotubes were used as the transparent top electrical contact in... more Thin films of single-wall carbon nanotubes were used as the transparent top electrical contact in Cu(In,Ga)Se 2 - based solar cells. Specifically, we demonstrate that thin layers of carbon nanotubes in combination with insulating polymer layers can effectively replace the metal oxide ...
Physical Review Letters, 2004
ABSTRACT
Physical Chemistry Chemical Physics, 2006
The endohedral fullerene epoxide N@C 60 O was synthesised, isolated by High Performance Liquid Ch... more The endohedral fullerene epoxide N@C 60 O was synthesised, isolated by High Performance Liquid Chromatography (HPLC), and characterised by Electron Spin Resonance (ESR). This nitrogen radical displays predominantly axial symmetry characteristics as expected for a monoadduct, evidenced by a zero-field splitting D parameter of 6.6 MHz and an E parameter of 0.5 MHz in powder at 77 K. Photo-and thermally-activated silencing of the nitrogen radical were observed, the latter showing the evolution of a new spin signal during heating at 100 1C. We suggest that loss of nitrogen spin is due to coupling with a radical formed by opening of the epoxide ring. This implies that the reaction of C 60 O with C 60 in the solid state proceeds via a radical, rather than ionic, intermediate.
… (PVSC), 2009 34th …, 2009
... DE-FG36-08G088005. The authors would like to acknowledge helpful discussions and data collect... more ... DE-FG36-08G088005. The authors would like to acknowledge helpful discussions and data collection with our collaborators at the National Renewable Energy Lab, especially Drs. Teresa Barnes and Tim Coutts. REFERENCES ...
Chemical Society Reviews, 2006
In this critical review we survey non-covalent interactions of carbon nanotubes with molecular sp... more In this critical review we survey non-covalent interactions of carbon nanotubes with molecular species from a chemical perspective, particularly emphasising the relationship between the structure and dynamics of these structures and their functional properties. We demonstrate the synergistic character of the nanotube-molecule interactions, as molecules that affect nanotube properties are also altered by the presence of the nanotube. The diversity of mechanisms of molecule-nanotube interactions and the range of experimental techniques employed for their characterisation are illustrated by examples from recent reports. Some practical applications for carbon nanotubes involved in non-covalent interactions with molecules are discussed.
Chemical Communications, 2004
Exohedrally functionalised fullerenes have been inserted in single-walled carbon nanotubes (SWNTs... more Exohedrally functionalised fullerenes have been inserted in single-walled carbon nanotubes (SWNTs) with the aid of supercritical carbon dioxide to form peapods; C 61 (COOEt) 2 are encapsulated in SWNTs in high yield, whereas C 61 (COOH) 2 aggregate via hydrogen bonding to form a supramolecular complex, which sterically hinders encapsulation and causes it to adhere to the exterior surface of the SWNTs.
Chemical Communications, 2005
We report the application of SWNTs as templates for forming covalent polymeric chains from C 60 O... more We report the application of SWNTs as templates for forming covalent polymeric chains from C 60 O reacting inside SWNTs; the resulting peapod polymer topology is different from the bulk polymer in that it is linear and unbranched. { Electronic supplementary information (ESI) available: HPLC and MS of C 60 O; SAED and HRTEM images of (C 60 O) n. See
![Research paper thumbnail of Controlled orientation of ellipsoidal fullerene C[sub 70] in carbon nanotubes](https://attachments.academia-assets.com/77979944/thumbnails/1.jpg)
](Applied Physics Letters, 2004
Density functional theory calculations predict two orientations for ellipsoidal C 70 fullerenes i... more Density functional theory calculations predict two orientations for ellipsoidal C 70 fullerenes inside single-walled carbon nanotubes ͑SWNTs͒ of different sizes: transverse orientation for C 70 in ͑11,11͒ nanotubes (dϭ14.9 Å) and longitudinal orientation for C 70 in ͑10,10͒ nanotubes (dϭ13.6 Å). SWNTs with these diameters have been prepared and filled with the C 70 fullerenes, and characterized by Raman spectroscopy and high-resolution transmission electron microscopy, showing the orientations predicted by theory.
Corrosion resistance is a critical property for semiconductor processing chamber components. Corr... more Corrosion resistance is a critical property for semiconductor processing chamber components. Corrosive plasmas are omnipresent is semiconductor deposition processes, including plasma enhanced chemical vapor deposition (PECVD), physical vapor deposition (PVD), and etching. Process chamber cleanliness during plasma processing is becoming increasingly important as device feature sizes shrink. Particles that originate from erosion of the chamber components can lead to device yield losses, and eventually will result in the process chamber requiring the replacement of chamber components that are exposed to such plasmas. Thus the chamber components coatings are critical for tool performance and uptime.
AIP Conference Proceedings, 2004
Carbon nanotubes can encapsulate several molecular species forming one-dimensional crystals. Usin... more Carbon nanotubes can encapsulate several molecular species forming one-dimensional crystals. Using previously reported methods we produced directly-bonded, asymmetric C60-C70 dimers and oxygen-bridged dimers of the type C60-O-C60. We present here microscopic evidence of filling single-walled carbon nanotubes (SWNTs) with the above fullerene dimers. The most important filling constraint is found to be the nanotube size. SWNTs with diameters around 1.6
Physical Review B, 2007
We report on a complete characterization of the optical dispersion properties of conducting thin ... more We report on a complete characterization of the optical dispersion properties of conducting thin films of single-wall carbon nanotubes ͑SWCNTs͒. The films studied exhibit sheet resistances between 50 and 1000 ⍀ / sq and optical transparencies between 65% and 95% on glass and quartz substrates. These films have the potential to replace transparent conducting oxides in applications such as photovoltaics and flat-panel displays; however, their optical properties are not sufficiently well understood. The SWCNT films are shown to be hole conductors, potentially enabling their use as hole-selective contacts and allowing alternative device designs. The fundamental optical, morphological, and electrical characteristics of the films are presented here, and a phenomenological optical model that accurately describes the optical behavior of the films is introduced. Particular attention is paid to ellipsometry measurements and thorough evaluation of the reflection and absorption spectra of the films.
Physical Review Letters, 2004
We have assembled molecular arrays of C 60 inside double-walled carbon nanotubes (DWNTs) with int... more We have assembled molecular arrays of C 60 inside double-walled carbon nanotubes (DWNTs) with internal diameters of 11-26 Å and directly observed the existence of different crystalline phases of C 60 previously predicted theoretically. The structure of the encapsulated C 60 crystal is defined by the internal diameter of the DWNT, as the molecules adjust their packing arrangement in order to maximize van der Waals interactions. We have also shown that fullerenes in C 60 @DWNT interact with the outer layer of DWNTs, as demonstrated by the efficient filling of DWNTs with internal diameters of less than 12 Å .
Spherical carbon cages of fullerene molecules interact by van der Waals forces to form close-pack... more Spherical carbon cages of fullerene molecules interact by van der Waals forces to form close-packed arrangements in the solid state, such as the face-centered cubic lattice formed by C60 at room temperature. [1] Owing to the low directionality and low energy of the interfullerene interactions neutral fullerene molecules (such as C60) are freely rotating in the crystal at room temperature. Contrasting to the empty fullerene cages, metal-containing endohedral fullerenes are known to have large electric dipole moments of 3–4 Debye. Therefore, it should be expected that intermolecular interactions in the solid M@Cn, (M=metal center) are dominated by strong dipolar interactions. For example, fullerene Ce@C82 has a large dipole moment owing to the transfer of three valence electrons from the Ce atom to C82 cage. [4] This fullerene crystallizes in a hexagonal or a face-centered cubic close pack arrangement. However, despite the dipole moment the fullerene Ce@C82 has been shown to retain it...
Aps Meeting Abstracts, 2004
ABSTRACT Using density functional theory calculations, the electronic structure of fullerene dime... more ABSTRACT Using density functional theory calculations, the electronic structure of fullerene dimers have been investigated which would be useful for quantum computing. We have studied two directly linked fullerenes forming a bridging ring (C60-C60 and C70-C60), and two fullerenes linked with additional bridging oxygen atom between them (C60-O-C60 and C70-O-C60). We have also identified the new geometry of C70-C-C60 which has a carbon bridging atom with four bonds to two fullerenes. The structural properties and electronic structures of each dimers have investigated theoretically, and compared to experimental observations. The numbers of stable isomers in each kind of dimers and relative stability of dimers have in good agreement with experimental results. We have also calculated doubly charged dimers in order to predict the applicability to quantum computing.
Journal of Physical Chemistry C, 2007
Thin films of single-wall carbon nanotubes were used as the transparent top electrical contact in... more Thin films of single-wall carbon nanotubes were used as the transparent top electrical contact in Cu(In,Ga)Se 2 - based solar cells. Specifically, we demonstrate that thin layers of carbon nanotubes in combination with insulating polymer layers can effectively replace the metal oxide ...
Physical Review Letters, 2004
ABSTRACT
Physical Chemistry Chemical Physics, 2006
The endohedral fullerene epoxide N@C 60 O was synthesised, isolated by High Performance Liquid Ch... more The endohedral fullerene epoxide N@C 60 O was synthesised, isolated by High Performance Liquid Chromatography (HPLC), and characterised by Electron Spin Resonance (ESR). This nitrogen radical displays predominantly axial symmetry characteristics as expected for a monoadduct, evidenced by a zero-field splitting D parameter of 6.6 MHz and an E parameter of 0.5 MHz in powder at 77 K. Photo-and thermally-activated silencing of the nitrogen radical were observed, the latter showing the evolution of a new spin signal during heating at 100 1C. We suggest that loss of nitrogen spin is due to coupling with a radical formed by opening of the epoxide ring. This implies that the reaction of C 60 O with C 60 in the solid state proceeds via a radical, rather than ionic, intermediate.
… (PVSC), 2009 34th …, 2009
... DE-FG36-08G088005. The authors would like to acknowledge helpful discussions and data collect... more ... DE-FG36-08G088005. The authors would like to acknowledge helpful discussions and data collection with our collaborators at the National Renewable Energy Lab, especially Drs. Teresa Barnes and Tim Coutts. REFERENCES ...
Chemical Society Reviews, 2006
In this critical review we survey non-covalent interactions of carbon nanotubes with molecular sp... more In this critical review we survey non-covalent interactions of carbon nanotubes with molecular species from a chemical perspective, particularly emphasising the relationship between the structure and dynamics of these structures and their functional properties. We demonstrate the synergistic character of the nanotube-molecule interactions, as molecules that affect nanotube properties are also altered by the presence of the nanotube. The diversity of mechanisms of molecule-nanotube interactions and the range of experimental techniques employed for their characterisation are illustrated by examples from recent reports. Some practical applications for carbon nanotubes involved in non-covalent interactions with molecules are discussed.
Chemical Communications, 2004
Exohedrally functionalised fullerenes have been inserted in single-walled carbon nanotubes (SWNTs... more Exohedrally functionalised fullerenes have been inserted in single-walled carbon nanotubes (SWNTs) with the aid of supercritical carbon dioxide to form peapods; C 61 (COOEt) 2 are encapsulated in SWNTs in high yield, whereas C 61 (COOH) 2 aggregate via hydrogen bonding to form a supramolecular complex, which sterically hinders encapsulation and causes it to adhere to the exterior surface of the SWNTs.
Chemical Communications, 2005
We report the application of SWNTs as templates for forming covalent polymeric chains from C 60 O... more We report the application of SWNTs as templates for forming covalent polymeric chains from C 60 O reacting inside SWNTs; the resulting peapod polymer topology is different from the bulk polymer in that it is linear and unbranched. { Electronic supplementary information (ESI) available: HPLC and MS of C 60 O; SAED and HRTEM images of (C 60 O) n. See
Applied Physics Letters, 2004
Density functional theory calculations predict two orientations for ellipsoidal C 70 fullerenes i... more Density functional theory calculations predict two orientations for ellipsoidal C 70 fullerenes inside single-walled carbon nanotubes ͑SWNTs͒ of different sizes: transverse orientation for C 70 in ͑11,11͒ nanotubes (dϭ14.9 Å) and longitudinal orientation for C 70 in ͑10,10͒ nanotubes (dϭ13.6 Å). SWNTs with these diameters have been prepared and filled with the C 70 fullerenes, and characterized by Raman spectroscopy and high-resolution transmission electron microscopy, showing the orientations predicted by theory.