Objective
The aim of this project is thus to study the optical absorption, the expansion, the structural parameters, ultrasonic attenuation and propagation speeds as a function of temperature in monocrystals of the type I-II-VI2 semiconductors.
Monocrystals of CaInSe2, CuInTe2, CuGaSe2, CuGaS2, CuInS2 and AgInTe2 have been grown; the first 3 by the directional solidification method, the remaining 3 by the chemical transport method. High temperature X-ray diffraction studies were made on the compounds CuInTe2 and AgInTe2. The results are in the process of being analysed. The determination of the structure of a CuGaS2 monocrystal was also made so as to investigate the electron density in the crystal. A study of lattice vibrations in CuInSe2 and CuGaSe2 has been made to help resolve a controversy which appeared in the literature on the spectrum of vibration of these two compounds. The results obtained remove all ambiguity and have been submitted for publication. Measurements of optical transmission were made between 5 K and 300 K. For CuInTe2 the variations with temperature in the width of the forbidden band Eg were determined and the deformation potential was calculated. For CuGaS2 the position of the first excitonic level was determined as well as the variation with temperature of the midheight width of this peak.
Topic(s)
Data not availableCall for proposal
Data not availableFunding Scheme
CSC - Cost-sharing contractsCoordinator
59655 Villeneuve d'Ascq
France