Photoluminescent properties of semiconducting Tl₆I₄Se

Abstract

The photoluminescence (PL) from the wide bandgap semiconductor Tl 6 I 4 Se, a promising candidate material for gamma ray detection, was studied at low temperature. The Tl 6 I 4 Se single crystal was grown by the Bridgman method. For undoped material, we observed a single broad peak at ∼1.61 eV with a full width at half maximum of 112 meV at 20 K, which is attributed to donor-acceptor pair (DAP) recombination involving shallow donors and deep acceptors. From the thermal quenching of the integrated PL peak intensity, thermal activation energy of the donor level of 52 meV was obtained. At high excitation intensities a blue-shift of peak emission energy in DAP recombination was observed. From the PL measurements, the ionization energies of the donor and acceptor levels were estimated at 52 and 290 meV, respectively.

Cs2MIIMIV3Q8 (Q = S, Se, Te): An Extensive Family of Layered Semiconductors with Diverse Band Gaps

“…A four zone temperature controlled furnace equipped with a lowering mechanism was used to perform a Bridgman crystal growth experiment for Cs 2 HgSn 3 Se 8 . − Five grams of pure material was first synthesized using the method described above. The products of this initial reaction were then removed from the tube and flame-sealed under vacuum in a 10 mm fused silica tube with a tapered end.…”

Photoluminescence fatigue and inhomogeneous line broadening in semi-insulating Tl6SeI4single crystals

“…Electrically active defects are particularly important because they influence both carrier mobility and recombination lifetime by acting as scattering and recombination centers as well as trapping centers. Previously recombination centers have been observed in Tl 6 SeI 4 prepared by the Bridgman crystal growth technique [8,9]. Photoluminescence (PL) measurements of Tl 6 SeI 4 single crystals revealed a broad emission band centered at 1.61 eV at 10 K, which was attributed to a donor-acceptor pair (DAP) recombination [9].…”

“…Previously recombination centers have been observed in Tl 6 SeI 4 prepared by the Bridgman crystal growth technique [8,9]. Photoluminescence (PL) measurements of Tl 6 SeI 4 single crystals revealed a broad emission band centered at 1.61 eV at 10 K, which was attributed to a donor-acceptor pair (DAP) recombination [9]. This band shows inhomogeneous line broadening with a full width at half maximum (FWHM) of 112 meV [9].…”

“…Photoluminescence (PL) measurements of Tl 6 SeI 4 single crystals revealed a broad emission band centered at 1.61 eV at 10 K, which was attributed to a donor-acceptor pair (DAP) recombination [9]. This band shows inhomogeneous line broadening with a full width at half maximum (FWHM) of 112 meV [9]. Based on density functional theory (DFT) calculations the observed emission was attributed to an antisite pair (I Se -Se I ), whose formation involves an interchange of the positions of a Se ion with its nearest-neighbor I ion [10].…”

Charge Transport Mechanisms in a Pb2P2Se6 Semiconductor

“…Recently, there has been considerable interest in identifying new low-cost, heavy element, chemical compounds as detector materials for room-temperature hard radiation detection. − Although cadmium zinc telluride (CZT) is undeniably the leading candidate material, its widespread deployment is impeded by high cost as well as structural imperfections . Our group has recently been investigating suitable cost-effective alternatives by expanding the pool of potential detector materials to comprise heavy element semiconducting compounds incorporating light p-block elements, such as Cl, S, and P. − Of particular interest is the heavy metal selenophosphate Pb 2 P 2 Se 6 . This stoichiometric ternary compound is a highly resistive (ρ ≈ 10 11 Ω-cm) semiconducting material with an indirect band gap of 1.88 eV at 295 K. Pb 2 P 2 Se 6 has an average atomic number ( Z ) of 39.8 and a high mass density of 6.14 g cm –3 , which result in a high attenuation coefficient for high-energy radiation .…”