RECOMBINATION KINETICS OF CDSIN

The luminescence of CdS: In crystals is investigated in the near band gap region by means of time resolved measurements in the ps regime. The changes of the electronic structure induced by the doping give rise to a pronounced decrease of the (D0, X) complex lifetime down to 30 ps at some 10(17) cm-3. At higher doping levels, the degeneracy of the conduction band results in radiative band-to-band transitions. The corresponding broad luminescence band decays exponentially within 300 ps. Under high excitation conditions, the recombination rate of band-to-band transitions in heavily doped samples increases strongly. For medium and low dopant concentrations, an increase of the excitation density results in longer decay times due to saturation.