Journal of Physical Studies 9(2), 177–181 (2005) DOI: https://doi.org/10.30970/jps.09.177 EFFECT OF THE ELECTRONIC STRUCTURE OF THE ETCHED CdTe SINGLE CRYSTALS ON THE EXCITON RADIATION PROCESSES P. M. Tkachuk1, V. I. Tkachuk1, S. V. Mel'nychuk1, M. V. Kurik2 1Fedkovych National University of Chernivtsi, 2 Kotsyubinskyi St., Chernivtsi, UA–58012, Ukraine 2Institute for Physics, National Academy of Science of Ukraine, 46, Nauka Ave., Kyiv, UA–03028, Ukraine

Under optical excitation the structure of the radiation beyond fundamental absorption of the orientated CdTe single crystals caused by $LO$-phonon scattering processes of the electron-hole states is observed. Crystals have been doped with impurity of Cl as a result of the surface preparing by etching in Br-methanol. Electronic structure of the single crystals surface layer is identified on the basis of two-phonon radiation absorption investigation. Peculiarities of the IR-spectra are in accordance with the modes selection rules in the point of Brillouin zone (BZ) characterized by lower symmetry than Г-minimum. The formation of the scattering phonons is explained by electronic undirect transitions into conduction band $Γ$-minimum from impurity band associated with Cl levels in $X$ point of BZ. Taking into account the modes selection rules the one and two phonon scattering mechanisms for two crystals surface orientations are determined.

PACS number(s): 71.55.-i

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