Intracenter radiative transitions at ZnSe:Fe impurity centers in the near infrared region of the spectrum

In the range 0.6–1.8$\mu$m, the luminescence spectral composition of ZnSe samples doped with an iron impurity by high-temperature thermal diffusion in a Zn or Ar atmosphere was studied. In the luminescence spectra of the samples, 980 and 1400nm lines, associated with intracenter radiative transitions at Fe$^{2+}$ centers, were observed. According to the data of spectral scanning, the intensities of both lines were correlated over the entire surface of the sample, which indicates that both radiative transitions occur at the same center. The radiative transitions were identified using the Tanabe–Sugano diagram with parameters adapted to ZnSe:Fe$^{2+}$ centers ($d^6$). The results indicate that the 980 and 1400nm lines are associated with the $^{3}T_{1}(^{3}H)$–$^{5}E(^{5}D)$ and $^{3}T_{1}(^{3}H)$–$^{5}T_{2}(^{5}D)$ electron transitions, respectively.