O. Stenzel et R. Petrich, OPTICAL-PERFORMANCE OF AMORPHOUS HYDROGENATED CARBON LAYERS - RANGE OF OPTICAL-CONSTANTS ACHIEVABLE, Optical engineering, 32(11), 1993, pp. 2951-2959
The optical properties of differently deposited amorphous carbon layer
s have been investigated by spectrophotometric means from the middle i
nfrared up to the visible spectral region. The optical constants of th
e layers could be calculated by a numerical procedure that combines fe
atures of single-wavelength methods and multiwavelength methods. Depen
ding on the deposition technique applied, the optical constants of the
layers have been found to vary over a wide range. Thus, refractive in
dex values could be established between 1.6 and 2.9, while IR-absorpti
on coefficients vary between 20/cm and 40,000/cm. The optical performa
nce of the layers is thus nonuniform and may be influenced by the sele
ction of suitable deposition parameters. Due to the potentially wide r
ange of optical constants of amorphous carbon, various possibilities e
xist for the application as an optical thin film material. Application
s such as selective absorber coatings for solar physical purposes are
discussed as well as mechanically and chemically resistant antireflect
ion coatings on high-refractive index semiconducting materials (silico
n, germanium).