@inproceedings{0794ae193c66488ebecc6048480d6d28,
title = "Thin film cavity ringdown spectroscopy and second harmonic generation on thin a-Si:H films",
abstract = "A set of 8 rf deposited a-Si:H thin films of various thickness (4-1031nm) have been used to explore the applicability of two optical techniques, thin film cavity ringdown spectroscopy (tf-CRDS) and second harmonic generation (SHG), for the measurement of small defect-related absorptions. In this paper we will give a first overview of the different aspects of these techniques, which are novel in the field of amorphous silicon materials. It is shown that tf-CRDS is capable of measuring defect-related absorptions (associated with dangling bonds) as small as 10-7 for a single measurement, without the need for elaborate calibration procedures. The results are compared with photothermal deflection spectroscopy (PDS) for a broad spectral range (0.7 -1.7 eV) and show good agreement. Furthermore the existence of a defect-rich surface layer with a defect density of 1.1 × 1012 cm-2 has been proven. The absorption spectrum of a 4 nm thin film has revealed a different spectral signature than a bulk dominated (1031 nm) film. The SHG experiments on a-Si:H films have shown that the second harmonic signal arises from the surface states and polarization dependent studies have revealed that the surface states probed have an ∞m-symmetry. From this it can be deduced that the absorbing surface states are isotropically distributed. A spectral scan suggests that the second harmonic signal, whose origin has not been unrevealed yet, has a resonance at an incident photon energy of 1.22 eV.",
author = "Aarts, {I. M.P.} and B. Hoex and Gielis, {J. J.H.} and Leewis, {C. M.} and Smets, {A. H.M.} and R. Engeln and M. Nesl{\'a}dek and Kessels, {W. M.M.} and {Van de Sanden}, {M. C.M.}",
year = "2003",
month = dec,
day = "1",
language = "English",
isbn = "1-558-99699-0",
series = "Materials Research Society Symposium Proceedings",
publisher = "Materials Research Society",
pages = "111--116",
editor = "J.R. Abelson",
booktitle = "Amorphous and nanocrystalline silicon-based films - 2003 : symposium held April 22 - 25, 2003, San Francisco, California, U.S.A.",
address = "United States",
note = "2003 Amorphous and Nanocrystalline Silicon-Based Films Symposium ; Conference date: 22-04-2003 Through 25-04-2003",
}