Energy levels of vanadium ions in CdTe

Abstract

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.