Optical properties of Cd(Ga_(1-x)Tm_x)_2S_4(x = 0.01) single crystals

摘要

Photoluminescence and absorption spectra of Cd(Ga_(0.99)Tm_(0.01))_2S_4 single crystals were investigated. We observed a broad and weak emission band at 4600 A, a relatively strong emission band at 6200 A, and several sharp and narrow emission bands in the wavelength region of 7600 to 8400 A in the photoluminescence spectrum at 4.8 K. The two broad emission bands observed in shorter wavelength regions correspond to donor-acceptor pair recombination. The ten sharp and narrow emission bands observed in the near infrared region are associated with the ~3F_4 → ~3H_6 transitions of Tm~(3+) ions. These bands were also observed in the optical absorption spectrum for the crystals. Twelve-absorption bands showed a difference from the emission bands in positions. The emission and absorption bands related to Tm~(3+) ions were discussed on the basis of crystal-field theory.