Abstract
In this article, we describe a parametric study of the effects of the size distribution (SD) and the concentration of nanospheres
in ethanol on the angular reflectance. Calculations are based on an effective medium approach in which the effective dielectric
constant of the mixture is obtained using the Maxwell–Garnett formula. The detectable size limits of gold, aluminum, and silver
nanospheres on a 50-nm-thick gold film are calculated to investigate the sensitivity of the reflectance to the SD and the
concentration of the nanospheres. The following assumptions are made: (1) the total number of particles in the unit volume
of suspension is constant, (2) the nanospheres in the suspension on a gold film have a SD with three different concentrations,
and (3) there is no agglomeration and the particles have a log-normal SD, where the effective diameter, d
eff and the effective variance, ν
eff are given. The dependence of the reflectance on the d
eff, ν
eff, and the width of the SD are also investigated numerically. The angular variation of the reflectance as a function of the
incident angle shows a strong dependence on the effective size of the metallic nanospheres. The results confirm that the size
of the nanospheres (d
eff <100 nm) can be detected by reflected light from the bottom surface of a gold film with a reasonable sensitivity if a proper
angle of incidence is chosen based on the type of metallic particles on a gold thin film at λ = 632 nm. We show that the optimum incident angle to characterize the size of nanospheres on a gold film is between 70° and
75° for a given concentration with a particular SD.
in ethanol on the angular reflectance. Calculations are based on an effective medium approach in which the effective dielectric
constant of the mixture is obtained using the Maxwell–Garnett formula. The detectable size limits of gold, aluminum, and silver
nanospheres on a 50-nm-thick gold film are calculated to investigate the sensitivity of the reflectance to the SD and the
concentration of the nanospheres. The following assumptions are made: (1) the total number of particles in the unit volume
of suspension is constant, (2) the nanospheres in the suspension on a gold film have a SD with three different concentrations,
and (3) there is no agglomeration and the particles have a log-normal SD, where the effective diameter, d
eff and the effective variance, ν
eff are given. The dependence of the reflectance on the d
eff, ν
eff, and the width of the SD are also investigated numerically. The angular variation of the reflectance as a function of the
incident angle shows a strong dependence on the effective size of the metallic nanospheres. The results confirm that the size
of the nanospheres (d
eff <100 nm) can be detected by reflected light from the bottom surface of a gold film with a reasonable sensitivity if a proper
angle of incidence is chosen based on the type of metallic particles on a gold thin film at λ = 632 nm. We show that the optimum incident angle to characterize the size of nanospheres on a gold film is between 70° and
75° for a given concentration with a particular SD.
- Content Type Journal Article
- Category Research Paper
- DOI 10.1007/s11051-010-0035-y
- Authors
- Mustafa M. Aslan, TUBITAK Marmara Research Center Materials Institute 41470 Gebze-Kocaeli Turkey
- Thomas Wriedt, Institut für Werkstofftechnik Badgasteiner Str. 3 28359 Bremen Germany
- Journal Journal of Nanoparticle Research
- Online ISSN 1572-896X
- Print ISSN 1388-0764
No comments:
Post a Comment