Figure 1
Luminescence decay time constants as a function of temperature, calculated using the two models discussed in the text. The parameters for the two-level model [a; equation (4)] are: = 10–5 s, K = 108 s–1 and = 0.2 eV. The parameters for the three-level model [b, equation (5)] are: k1 = 5 × 103 s–1, k2 = 2 × 105 s–1, D = 0.005 eV, K = 108 s–1 and = 0.2 eV. |