Temperature dependence of the fundamental absorption edge in CuGa3Se5

From the study of the temperature dependence of the optical absorption spec tra, the energy gap of the ordered vacancy compound CuGa3Se5 between 10 and 300 K are calculated using the model proposed by Elliot (Phys. Rev. 108 (1 957) 1384). This variation is analyzed by using the semi-empirical relation suggested by Manoogian and Woolley (Can. J. Phys. 62 (1984) 285). The temp erature variation of the free exciton binding energy, the Debye temperature , the dielectric constant, and the effective masses of free excitons, elect rons and holes are estimated from the adjustable parameters of these models . (C) 1999 Published by Elsevier Science S.A.