Green emission and bandgap narrowing due to two-photon excitation in thin film CdS formed by spray pyrolysis

Authors
Ullrich, B Schroeder, R
Citation
B. Ullrich et R. Schroeder, Green emission and bandgap narrowing due to two-photon excitation in thin film CdS formed by spray pyrolysis, SEMIC SCI T, 16(8), 2001, pp. L37-L39
Citations number
16
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
SEMICONDUCTOR SCIENCE AND TECHNOLOGY
ISSN journal
02681242 → ACNP
Volume
16
Issue
8
Year of publication
2001
Pages
L37 - L39
Database
ISI
SICI code
0268-1242(200108)16:8<L37:GEABND>2.0.ZU;2-N
Abstract
Thin (10 mum) film CdS on Pyrex (R) formed by spray pyrolysis is excited be low the gap at 804 nm with 200 fs laser pulses at room temperature. Excitat ion intensities up to 250 GW cm(-2) evoke green bandgap emission due to two -photon transitions. This two-photon photoluminescence does not show a red emission contribution in contrast to the single-photon excited emission, wh ich is dominated by broad emission in the red spectral range. It is demonst rated that two-photon excitation causes photo-induced bandgap narrowing due to Debye screening. At 250 GW cm(-2) bandgap narrowing of 47 meV is observ ed, which corresponds to an excited electron density of 1.6 x 10(18) cm(-3) .