Excitation intensity and temperature‐dependent photoluminescence and optical absorption in Tl₄Ga₃InSe₈ layered crystals

Abstract

Photoluminescence (PL) spectra of Tl 4 Ga 3 InSe 8 layered crystals grown by Bridgman method have been studied in the wavelength region of 600-750 nm and in the temperature range of 17-68 K. A broad PL band centered at 652 nm (1.90 eV) was observed at T = 17 K. Variations of emission band has been studied as a function of excitation laser intensity in the 0.13 to 55.73 mW cm -2 range. Radiative transitions from donor level located at 0.19 eV below the bottom of conduction band to shallow acceptor level located at 0.03 eV above the top of the valence band were suggested to be responsible for the observed PL band. From X-ray powder diffraction and optical absorption study, the parameters of monoclinic unit cell and the energy of indirect band gap were determined, respectively.

Thermally stimulated current observation of trapping centers in an undoped Tl4Ga3InSe8 layered single crystal

“…At this point, it is worthwhile to compare the present results with those obtained in our previous study of Tl 4 Ga 3 InSe 8 crystal using PL spectroscopy, which yielded a level at 30 meV [8]. This energy level was obtained from the temperature dependence of the PL intensity.…”

“…X-ray powder diffraction, optical absorption and photoluminescence (PL) in the layered semiconductor Tl 4 Ga 3 InSe 8 were reported in Ref. [8]. The parameters of the monoclinic unit cell were found to be a = 1.0855, b = 1.0850 and c = 1.5650 nm, and β = 100.58°.…”