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Electroreflectance on Trigonal Selenium
Author(s) -
Weiser G.,
Stuke J.
Publication year - 1971
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2220450234
Subject(s) - brillouin zone , condensed matter physics , trigonal crystal system , electric field , chemistry , exciton , selenium , piezoelectricity , band gap , polarization (electrochemistry) , physics , crystallography , crystal structure , organic chemistry , quantum mechanics , acoustics
Measurements of transverse electroreflectance and of its temperature dependence were performed on trigonal selenium crystals in the energy region between 1.8 and 4.2 eV. The observed structures which show a strong dependence on polarization of light and on orientation of electric field are mainly correlated to exciton transitions. The discussion of the results gives a good accordance with band structure calculations. The direct gap is located at point H of the Brillouin zone and shows a positive temperature coefficient between 5 and 160°K. The first valence band is split into three subbands which lie close together with distances of 42 and 13 meV. Besides the electroreflectance spectrum which is independent of the direction of electric field a signal is observed which depends on its sign. Probably this spectrum is due to lattice deformation created by piezoelectric effect.