Luminescence spectroscopy of iron-doped KTaO₃ crystals

Abstract

KTaO₃ crystals slightly doped with iron were investigated by luminescence spectroscopy. A zero-phonon line was found in the low-temperature emission at 14569 cm⁻¹ under excitation in the spectral region 15000–24000 cm⁻¹. The results suggest that this luminescence originates from Fe³⁺ (d ⁵) ions substituted for K⁺. The excitation and emission are assigned to the ⁶A₁(S) → ⁴T₁(G), ²T₂(I), ⁴T₂(G), and ⁴T₁(G) → ⁶A₁(S) transitions, respectively. The following crystal field parameters of Fe³⁺ in KTaO₃ were found: Dq = 1230 cm⁻¹ B = 690 cm⁻¹, and C = 3452 cm⁻¹.

Key Words:

• Photoluminescence
• Potassium tantalate
• Iron
• Zero-phonon line