Size-Quantized Excitons in Microcrystals of Cuprous Halides Embedded in Alkali-Halide Matrices

Exciton luminescence spectra in CuCl, CuBr, and CuI microcrystals of a few nm in size which are embedded in alkali-halide matrices are studied under selective excitation at the exciton absorption bands inhomogeneously broadened by the size distribution. The size-quantized exciton states are found to split into various components. From the analysis of the splitting on the basis of the size-quantization of the exciton translational motion in the microcrystals of thin platelets, the Z3 exciton translational mass, the Luttinger parameters, and k-linear terms for the Z1,2 excitons are derived in these compounds. Les spectres de luminescence excitonique de microcristaux de CuCl, CuBr et de CuI ayant, des dimensions de quelques nm enfouis dans des matrices de halogenures alcalins alcalins sont etudies par excitation selective dans la bande d'absorption excitonique, celle-ci etant elargie de facon in homogene a cause de la distribution en dimension des microcristaux. On observe une separation en differentes composantes des etats excitoniques quantifies en dimension. A partir de l'analyse de cette separation des niveaux nous obtenons la masse translationnelle de l'exciton Z3, les parametres de Luttinger de l'exciton et les termes lineaire en k des exciton Z1,2 dans ces trois composes.