Optical detection of melting point depression for silver nanoparticles via <i>in situ</i> real time spectroscopic ellipsometry

Little, Scott; Bégou, Thomas; Collins, R. W.; Marsillac, Sylvain

doi:10.1063/1.3681367

Cited by 52 publications

(25 citation statements)

References 10 publications

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“…For example, Yeschenko et al 9 showed that the melting point of silver nanoparticles embedded in a silica matrix varied between 350 o C (30 nm diameter) and 160 o C (8 nm diameter). A reduction in the melting temperature was also seen recently by Little et al for silver films formed into nanometer sized islands on Si substrates 10 ; both approaches employed optical (plasmon based) methods to determine the onset of melting.…”

Section: Introductionsupporting

confidence: 57%

Enhanced Electrical Conductivity of Silver Nanoparticles for High Frequency Electronic Applications

Alshehri

Jakubowska

Machová

et al. 2012

ACS Appl. Mater. Interfaces

156

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An enhancement in the electrical performance of low temperature screen-printed silver nanoparticles (nAg) has been measured at frequencies up to 220 GHz. We show that for frequencies above 80 GHz the electrical losses in coplanar waveguide structures fabricated using nAg at 350 o C are lower than those found in conventional thick film Ag conductors consisting of micron-sized grains and fabricated at 850 o C. The improved electrical performance is attributed to the better packing of the silver nanoparticles resulting in lower surface roughness by a factor of three. We discuss how the use of silver nanoparticles offers new routes to high frequency applications on temperature sensitive conformal substrates and in sub-THz metamaterials.

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Section: Introductionsupporting

confidence: 57%

Enhanced Electrical Conductivity of Silver Nanoparticles for High Frequency Electronic Applications

Alshehri

Jakubowska

Machová

et al. 2012

ACS Appl. Mater. Interfaces

156

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“…The shape deformation and melting point decrease of nanoparticles was observed and described earlier for different types of nanoparticles [13][14][15][16]. The lower melting point compared to the bulk material is due to the large surface-to-volume ratio, which results in an increase in the surface free energy of the particles [17].…”

Section: Introductionmentioning

confidence: 87%

Thermal stability of mesoporous silica-coated gold nanorods with different aspect ratios

Gergely-Fülöp

Zámbó

Deák

2014

Materials Chemistry and Physics

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The effect of different temperatures (up to 900 °C) on the morphology of mesoporous silicacoated gold nanorods was systematically investigated. Gold nanorods with different aspect ratios (AR ranging from 2.5 to 4.3) were coated with a 15 nm thick mesoporous silica shell.Silicon supported monolayers of the particles were annealed in the temperature range of 300-900 °C. The resulting changes in particle morphology were investigated using scanning electron microscopy and visible wavelength extinction spectroscopy. The silica coating generally improved the stability of the nanorods from ca. 250 °C by several hundreds degree Celsius. For nanorods with AR<3 the shape and the aspect ratio change is only moderate up to 700 °C. At 900 °C these nanorods became spherical. For nanorods with AR>3, lower stability was found as the aspect ratio decrease was more significant and they transformed into spherical particles already at 700 °C. It was confirmed by investigating empty silica shells that the observed conformal change of the shell material when annealing core/shell particles is dictated by the deformation of the core particle. This also implies that a significant mechanical stress is exerted on the shell upon core deformation. In accordance with this, for the highest aspect ratio (AR~4) nanorod the shell breaks up at 900 °C and the gold cores were partially released and coalesced into large spherical particles.

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“…Consistency is suggested because highly disordered or even liquid films are expected to exhibit a single TL and can form atomically smooth surfaces upon coalescence [51]. A liquid film is a possibility due to the reduction in the melting point from the bulk that can occur in clusters and very thin films, as observed in RTSE studies of Ag thin film deposition [52]. It is of interest to note that the compositions with the most rapid smoothening effect during coalescence are those that exhibit the highest performance when incorporated into devices.…”

Section: Rtse Results and Discussionmentioning

confidence: 99%

Real Time Spectroscopic Ellipsometry Analysis of First Stage CuIn1−xGaxSe2 Growth: Indium-Gallium Selenide Co-Evaporation

et al. 2018

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Real time spectroscopic ellipsometry (RTSE) has been applied for in-situ monitoring of the first stage of copper indium-gallium diselenide (CIGS) thin film deposition by the three-stage co-evaporation process used for fabrication of high efficiency thin film photovoltaic (PV) devices. The first stage entails the growth of indium-gallium selenide (In1−xGax)2Se3 (IGS) on a substrate of Mo-coated soda lime glass maintained at a temperature of 400 °C. This is a critical stage of CIGS deposition because a large fraction of the final film thickness is deposited, and as a result precise compositional control is desired in order to achieve the optimum performance of the resulting CIGS solar cell. RTSE is sensitive to monolayer level film growth processes and can provide accurate measurements of bulk and surface roughness layer thicknesses. These in turn enable accurate measurements of the bulk layer optical response in the form of the complex dielectric function ε = ε1 − iε2, spectra. Here, RTSE has been used to obtain the (ε1, ε2) spectra at the measurement temperature of 400 °C for IGS thin films of different Ga contents (x) deduced from different ranges of accumulated bulk layer thickness during the deposition process. Applying an analytical expression in common for each of the (ε1, ε2) spectra of these IGS films, oscillator parameters have been obtained in the best fits and these parameters in turn have been fitted with polynomials in x. From the resulting database of polynomial coefficients, the (ε1, ε2) spectra can be generated for any composition of IGS from the single parameter, x. The results have served as an RTSE fingerprint for IGS composition and have provided further structural information beyond simply thicknesses, for example information related to film density and grain size. The deduced IGS structural evolution and the (ε1, ε2) spectra have been interpreted as well in relation to observations from scanning electron microscopy, X-ray diffractometry and energy-dispersive X-ray spectroscopy profiling analyses. Overall the structural, optical and compositional analysis possible by RTSE has assisted in understanding the growth and properties of three stage CIGS absorbers for solar cells and shows future promise for enhancing cell performance through monitoring and control.

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Optical detection of melting point depression for silver nanoparticles via in situ real time spectroscopic ellipsometry

Cited by 52 publications

References 10 publications

Enhanced Electrical Conductivity of Silver Nanoparticles for High Frequency Electronic Applications

Enhanced Electrical Conductivity of Silver Nanoparticles for High Frequency Electronic Applications

Thermal stability of mesoporous silica-coated gold nanorods with different aspect ratios

Real Time Spectroscopic Ellipsometry Analysis of First Stage CuIn1−xGaxSe2 Growth: Indium-Gallium Selenide Co-Evaporation

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