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要旨:
In CdTe doped with vanadium the photoluminescence due to the 3 T 2(F) → 3 A 2(F) transition of V3+(d 2) is detected. Its decay time is determined as (630±20) μs, a result comparable to the analogous emissions in various host lattices. Further emissions around 5000 cm−1 and 9000 cm−1 are caused by charge-transfer transitions or bound-exciton decay. Excitation and sensitization spectra yield information on the positions of the energy levels within the gap, which are discussed using two different models. At T=4.2 K, the distance of the V2+/V3+ donor level is 7300 cm−1 and 5700 cm−1 referred to the valence and the conduction band edges, respectively. The absence of V2+(d 3) centres is tentatively ascribed to the existence of deeply bound excitons.