Thermally Robust Gold and Silver Iminopyrrolidinates for Chemical Vapor Deposition of Metal Films

Coyle, Jason P.; Gordon, Peter G.; Wells, Adam; Mandia, David J.; Sirianni, Eric R.; Yap, Glenn P. A.; Barry, Seán T.

doi:10.1021/cm402658c

Cited by 32 publications

(53 citation statements)

References 57 publications

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“…Since we are interested in these compounds as volatile precursors, we determined the temperature that produced sufficient volatility (1 Torr) using a stepped isothermal TGA. 49,50 This method utilizes the known vapour pressure of Cu(tmhd) 2 and comparison of its volatility to that of 1 or 2. 51 Single-source, hot-walled CVD experiments were performed using 1 and 2 over a substrate temperature range of 150 -500 ºC using Si [100] substrates on a home-built apparatus.…”

Section: Resultsmentioning

confidence: 99%

Surfactant Directed Growth of Gold Metal Nanoplates by Chemical Vapor Deposition

et al. 2015

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Surface-supported, low-dimensional gold nanostructures are of interest for plasmonic applications. Low dimensional nanostructures are readily accessible by solution-phase growth, where shape control through the addition of growthdirecting surfactants is well established. Yet, shape control in chemical vapour deposition (CVD) has not been well explored, and metallic gold films are typically limited to nanoparticulate or thin film morphologies. This article describes the self-seeded growth of high aspect ratio gold plates and wires by CVD. A directed growth mechanism is proposed, where growth is directed by the coordinating N-heterocyclic carbene (NHC) and phosphine ligands originating from the thermal decomposition of the two gas-phase precursors, [Au(HMDS)(NHC)] (HMDS = hexamethyldisilazide, NHC = 1,3-diisopropyl-imidazolidin-2-ylidene) and [Au(HMDS)(PMe 3 )]. These ligands acted as transient surfactants for plate growth between 370 and 460°C and at high precursor flux. Energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) evidence indicates that hydroxyl terminated substrate surfaces are passivated with trimethylsilyl (TMS) moieties originating from the HMDS ligand in both precursors, which promoted island type growth and directed precursor decomposition to occur on gold surfaces. Secondary nucleation is observed on all gold structures, and is a crucial component to gas-phase surfactant-mediated CVD growth. This work identifies the potential to use precursor-bound coordinative ligands or gas-phase surfactants to direct growth of metal nanocrystals by CVD.

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Section: Resultsmentioning

confidence: 99%

Surfactant Directed Growth of Gold Metal Nanoplates by Chemical Vapor Deposition

et al. 2015

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“…However, if the metal film has great aggregation in the structure caused by deposition conditions, such as slow deposition rate and/or high substrate temperature [12], the complex refractive index shows much higher real part and lower imaginary part than the bulk values. Therefore, with slow deposition rate of ~1 nm/min and high substrate temperature of 350 °C in the gold CVD [9], it is reasonable for the obtained anomalous refractive index caused by the highly-aggregated gold NPs shown in Fig. 2.…”

Section: Resultsmentioning

confidence: 80%

“…After the substrate achieved constant temperature, the evaporator was heated to a temperature of ~160 °C to initiate volatilization of the precursor. When the temperature reaches the volatilization point of the gold precursor (~130 °C), the vaporous precursor would saturate the chamber, effectively depositing at all exposed surfaces including the cladding of the TFBG [9]. By using this thermally stable gold precursor, the thickness and position of the gold film can be controlled by adjusting the amount of precursor and the temperature of the deposition chamber.…”

Section: Introductionmentioning

confidence: 99%

Anomalous refractive index of ultrathin gold nanoparticle film coated on tilted fiber Bragg grating

et al. 2014

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Effectively size-dependent refractive index of ultrathin gold film deposited by chemical vapour deposition (CVD) is experimentally investigated at infrared wavelength. By coating the gold film on tilted fiber Bragg grating (TFBG), the wavelength and amplitude of the TFBG cladding modes are modulated by the interaction between their evanescent fields and the gold film. Then, the complex refractive index of the gold film in in-plane and out-of-plane directions can be calculated from the effective indices of the cladding modes with azimuthally and radically polarized electric fields at cladding boundary, respectively. The obtained real parts of the complex refractive indices are about 10 times higher than that of bulk gold, for the gold films with thickness from 6 to 65 nm, while the imaginary parts are 2 orders of magnitude lower than the bulk value in the both of directions. Based on the Atomic force microscope and scanning electron microscope images of the gold films with different thicknesses, the aggregation of gold nanoparticles (NPs) caused by high substrate temperature and low deposition rate is considered as the main contribution to the anomalous refractive indices.

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“…This was rather high when compared to the 3.2 at.-% carbon content found in the gold films obtained from gold (I) iminopyrrolidinates. 9 The latter films were subject to further study, particularly due to their isotropic optical behaviour and therefore lack of polarization dependence. There was precedence in the literature 18,19 to employ a thin dielectric layer (Al2O3) over the TFBG prior to deposition of the gold overlayer in order to allow a larger wavelength separation of the TFBG resonance modes and enhance the polarization-dependence in the P-polarized peak family by increasing the SRI sensitivity of the TFBG.…”

Section: Resultsmentioning

confidence: 99%

“…The gold-containing guanidinate and iminopyrrolidinate CVD precursors, (1)[Au(N i Pr)2CN(Me)2]2 and (2) [Au(Me2-t Bu-ip)]2, respectively, were synthesized according to protocols reported elsewhere. 8,9 The TFBG is fed through a groove that was milled and epoxied into a KF-25 flange cap and sits directly above the single-source precursor boat in the case of (1) and in a separately heated bubbler in the case of (2). In all cases, the precursor is typically loaded into a bubbler within a drybox under N 2 atmosphere for safe transfer to the CVD apparatus prior to each experiment.…”

Section: Introductionmentioning

confidence: 99%

Chemical vapor deposition of anisotropic ultrathin gold films on optical fibers: real-time sensing by tilted fiber Bragg gratings and use of a dielectric pre-coating

Mandia

Zhou²,

Ward

et al. 2014

SPIE Proceedings

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Tilted fiber Bragg gratings (TFBGs) are refractometry-based sensor platforms that have been employed herein as devices for the real-time monitoring of chemical vapour deposition (CVD) in the near-infrared range (NIR). The coreguided light launched within the TFBG core is back-reflected off a gold mirror sputtered onto the fiber-end and is scattered out into the cladding where it can interact with a nucleating thin film. Evanescent fields of the growing gold nanostructures behave differently depending on the polarization state of the core-guided light interrogating the growing film, therefore the resulting spectral profile is typically decomposed into two separate peak families for the orthogonal S-and P-polarizations. Wavelength shifts and attenuation profiles generated from gold films in the thickness regime of 5-100 nm are typically degenerate for deposition directly onto the TFBG. However, a polarization-dependence can be imposed by adding a thin dielectric pre-coating onto the TFBG prior to using the device for CVD monitoring of the ultrathin gold films. It is found that addition of the pre-coating enhances the sensitivity of the P-polarized peak family to the deposition of ultrathin gold films and renders the films optically anisotropic. It is shown herein that addition of the metal oxide coating can increase the peak-to-peak wavelength separation between orthogonal polarization modes as well as allow for easy resonance tracking during deposition. This is also the first reporting of anisotropic gold films generated from this particular gold precursor and CVD process. Using an ensemble of x-ray techniques, the local fine structure of the gold films deposited directly on the TFBG is compared to gold films of similar thicknesses deposited on the Al2O3 pre-coated TFBG and witness slides.

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Thermally Robust Gold and Silver Iminopyrrolidinates for Chemical Vapor Deposition of Metal Films

Cited by 32 publications

References 57 publications

Surfactant Directed Growth of Gold Metal Nanoplates by Chemical Vapor Deposition

Surfactant Directed Growth of Gold Metal Nanoplates by Chemical Vapor Deposition

Anomalous refractive index of ultrathin gold nanoparticle film coated on tilted fiber Bragg grating

Chemical vapor deposition of anisotropic ultrathin gold films on optical fibers: real-time sensing by tilted fiber Bragg gratings and use of a dielectric pre-coating

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