EXCITONIC RESONANCE RAMAN-SCATTERING FROM OPTIC POLAR PHONONS IN AGGAS2

Authors
DEB SK ROY AP
Citation
Sk. Deb et Ap. Roy, EXCITONIC RESONANCE RAMAN-SCATTERING FROM OPTIC POLAR PHONONS IN AGGAS2, Solid state communications, 90(1), 1994, pp. 7-11
Citations number
8
Categorie Soggetti
Physics, Condensed Matter
Journal title
Solid state communications → ACNP
ISSN journal
00381098
Volume
90
Issue
1
Year of publication
1994
Pages
7 - 11
Database
ISI
SICI code
0038-1098(1994)90:1<7:ERRFOP>2.0.ZU;2-K
Abstract
The low temperature optical properties of the chalcopyrite semiconduct or AgGaS2 is dominated by well defined excitonic level. We report here exciton mediated resonance Raman scattering from B2(LO) and E(LO) pol ar phonons at 235 cm-1 and 230 cm-1 respectively as a function of temp erature over 20K to 200K. The variation in resonance enhancement of th ese modes with temperature could be explained assuming an exciton widt h of the form GAMMA(T)= a + bT + cT2 ie,the exciton decaying into one and two acoustic phonons. The agreement between the experiment and the ory is very good. We also argue that the enhancement is due to Frohlic h forbidden LO phonon-exciton coupling.