https://doi.org/10.1140/epjb/e2013-30595-4
Regular Article
Wavelength modulated excitonic spectra of Cu2O thin films sandwiched by MgO plates*
1
Graduate School of Science and Technology, Kumamoto University,
2-39-1, Kurokami Chuo-ku,
860-8555
Kumamoto,
Japan
2
Shockwave and Condensed Matter Research Center, Kumamoto
University, 2-39-1, Kurokami
Chuo-ku, 860-8555
Kumamoto,
Japan
a
e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Received: 13 July 2012
Received in final form: 24 December 2012
Published online: 29 April 2013
Abstract
We have investigated stress effects on yellow exciton states in a Cu2O thin film sandwiched by MgO plates by measuring wavelength modulated (WM) absorption spectra and their thermal variations. In the WM absorption spectra, dispersive spectral structures owing to 2P~4P states in the yellow excitons are clearly resolved in the thin film sample. A stress due to the lattice mismatch between Cu2O and MgO provides a large red shift of the band gap in the green excitonic system. However, in the yellow excitonic transitions, it is found that a red-shift of the 2P excitonic state is much smaller than that in the green excitonic system. This result suggests that a shallow potential minimum for the yellow excitons is built up in the Cu2O thin film sandwiched by MgO plates.
Contribution to the Topical Issue “Excitonic Processes in Condensed Matter, Nanostructured and Molecular Materials”, edited by Maria Antonietta Loi, Jasper Knoester and Paul H.M. van Loosdrecht.
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag, 2013
