Anomalous dependence of photoluminescence properties on composition x in Cd _{1– x} Mn _x Ga ₂ S ₄ mixed crystals

Abstract

PACS 78.55.HxPhotoluminescence spectra of Cd 1−xMnxGa2S4 mixed crystals were investigated in the composition region of 0.00 ≤ x ≤ 1.00 and in the temperature region of 6 to 300 K. The photoluminescence spectrum of CdGa 2 S 4 (x = 0.00) showed two emission bands at 594 nm (2.09 eV) and 460 nm (2.70 eV), which were attributed to be due to donor-acceptor pair recombination. The same feature of these bands was also observed for the crystals doped with 5 mol% Mn, excepting a slightly red shift and a decreasing of the halfwidth of the emission band in the longer wavelength region. For the crystals in the composition region of x ≤ 0.67, only the emission band in the longer wavelength region were observed. The photoluminescence spectra of MnGa 2S4(x = 1.00) showed a broad emission band 675 nm (1.838 eV), which is different from that of CdGa 2S4. The relative intensity of the main emission band increased in the composition region of 0.00 ≤ x ≤ 0.67 with increasing x while decreased in the region of 0.90 ≤ x ≤ 1.00. The anomalous composition dependence was connected with an occurrence of a miscibility gap of the crystal structure in that region.

Bulk Modulus, Elastic Constants, and Force Constants of Interatomic Bonds of II–III2–VI4 Compounds

“…[ 2 ] These compounds are characterized by birefringence, significant values of the coefficient of nonlinear susceptibility, and bright photoluminescence. [ 3 ] The presence of a wide bandgap (≈2–4 eV) and high photosensitivity stimulates the creation of ultraviolet radiation detectors, which are already used in medicine, biology, space physics, and other fields. Crystals of the II–III 2 –VI 4 group, CdGa 2 S 4 in particular, are promising materials for creating tunable narrow‐band optical filters due to the presence of the so‐called “isotropic point,” where the dispersion curves of the ordinary and extraordinary refractive indices intersect.…”