Optical functions of discontinuous aluminum films: Intraband and interband contributions to particle resonance absorption

Journal Article · Mon Mar 01 04:00:00 EST 1993 · Journal of the Optical Society of America, Part A: Optics and Image Science; (United States)

DOI:https://doi.org/10.1364/JOSAA.10.000515· OSTI ID:6608823

Nguyen, H V; Collins, R W ^[1]

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1. Pennsylvania State Univ., University Park (United States)

The authors have developed a comprehensive optical model that accounts for the continuous evolution of the effective optical functions of discontinuous Al (particle) films in the vicinity of the resonance absorption feature as a function of the particle size. They obtain unprecedented agreement between the calculated and experimental results for both real and imaginary parts of the effective dielectric functions of particle films that are from 1 to 6 nm in thickness. The experimental studies rely on a unique rapid-scanning multichannel ellipsometer to collect ([psi],[Delta]) spectra from 1.3 to 4.0 eV during Al particle-film growth by evaporation an sputtering onto SiO[sub 2]/c-Si substrates. In a least-squares regression analysis the effective dielectric functions that the authors obtained experimentally are fitted to a generalized Maxwell-Garnett effective-medium theory with three free parameters. Two parameters describe the particle-film morphology. The third parameter is the mean free path, which they assume to be common to electrons that participate in both intraband and interband transitions. From the modeling they find that the optical functions of the particles themselves are remarkably independent of size and shape as well as of the method of preparation. This is presumably because scattering at defects that are internal to the particles determines the electron relaxation time. The simplifying assumption regarding particle-film morphology (i.e., identical spheroids) does not appear to compromise these conclusions. From the overall study they conclude that the crystalline quality of substrate-supported metallic particles as small as 0.5 nm in radius can be assessed solely from noninvasive real-time spectroscopic ellipsometry measurements. 38 refs., 5 figs.

• OSTI ID: 6608823
• Journal Information: Journal of the Optical Society of America, Part A: Optics and Image Science; (United States), Journal Name: Journal of the Optical Society of America, Part A: Optics and Image Science; (United States) Vol. 10:3; ISSN 0740-3232; ISSN JOAOD6
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104 -- Metals & Alloys-- Physical Properties
661300* -- Other Aspects of Physical Science-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABSORPTION
ALUMINIUM
DATA
ELECTRONS
ELEMENTARY PARTICLES
ELEMENTS
ELLIPSOMETRY
EXPERIMENTAL DATA
FERMIONS
FILMS
INFORMATION
LEPTONS
MATHEMATICS
MEAN FREE PATH
MEASURING METHODS
METALS
MORPHOLOGY
NUMERICAL DATA
OPTICAL MODELS
OPTICAL PROPERTIES
PARTICLE SIZE
PARTICLES
PHYSICAL PROPERTIES
REGRESSION ANALYSIS
RELAXATION TIME
RESONANCE ABSORPTION
SCATTERING
SIZE
SORPTION
SPECTRA
SPHEROIDS
SPUTTERING
STATISTICS