|
Title
|
|
|
|
On the optical constants of amorphous thin films of non-uniform thickness prepared by plasma-enhanced chemical vapour deposition
|
|
|
Author
|
|
|
|
|
|
|
Abstract
|
|
|
|
| The preparation of layers of amorphous Ge(x)Se(1-x) (with Ge atomic concentrations x = 0, 0.17, 0.25 and 0.34) by plasma-enhanced chemical vapour deposition (PECVD) using the hydrides, GeH(4) and H(2)Se, as precursor gases is described in detail. Information concerning the structure of the films was obtained from Raman spectroscopy. The optical transmission was measured over the 300 to 2500 nm spectral region in order to derive the refractive index and extinction coefficient of these PECVD films. The expressions proposed by Swanepoel, enabling the calculation of the optical constants of a thin film with nonuniform thickness, have successfully been applied. The refractive-index dispersion data were analysed using the Wemple-DiDomenico single-oscillator fit. The optical-absorption edges have been all of them described using the 'non-direct transition' model proposed by Tauc. The optical gaps were calculated using Tauc's extrapolation, resulting in values ranging from 1.93 eV for a-Se to 2.26 eV for a-GeSe(2). (C) 1998 Elsevier Science Ltd. All rights reserved. |
|
|
|
Language
|
|
|
|
English
|
|
|
Source (journal)
|
|
|
|
Vacuum: the international journal and abstracting service for vacuum science and technology. - Oxford
|
|
|
Source (book)
|
|
|
|
2nd European Conference on Hard Coatings (ETCHC-2)/3rd Iberian Vacuum, Meeting (3rd RIVA), SEP 22-24, 1997, LISBON, PORTUGAL
|
|
|
Publication
|
|
|
|
Oxford
:
1999
|
|
|
ISSN
|
|
|
|
0042-207X
|
|
|
DOI
|
|
|
|
10.1016/S0042-207X(98)00233-4
|
|
|
Volume/pages
|
|
|
|
52
:1-2
(1999)
, p. 55-60
|
|
|
ISI
|
|
|
|
000077936500011
|
|
|
Full text (Publisher's DOI)
|
|
|
|
|
|
|
Full text (publisher's version - intranet only)
|
|
|
|
|
|