TY - JOUR
T1 - Optical investigation of defects in semi-insulating Tl6 I4S single crystals
AU - Peters, J. A.
AU - Sebastian, M.
AU - Nguyen, S.
AU - Liu, Zhifu
AU - Im, Jino
AU - Freeman, Arthur J
AU - Kanatzidis, Mercouri G
AU - Wessels, B. W.
PY - 2014/7/18
Y1 - 2014/7/18
N2 - Native defect levels in ternary compound Tl6I4S single crystals were studied by low-temperature photoluminescence (PL) and photoconductivity (PC) measurements. From the PL measurements, a broad emission band centered at 1.64 eV was observed at low temperatures. The peak can be decomposed using two standard Gaussian functions to reveal two emission bands at 1.55 and 1.66 eV. The PL peak at 1.55 eV is attributed to donor-acceptor pair recombination between a sulphur vacancy (VS) deep donor (Ed=0.57eV) and an antisite defect (SI) shallow acceptor (Ea=20meV). The 1.66-eV emission band is attributed to self-activated luminescence involving a defect complex and is described using a configuration coordinate model. Within this framework, the 1.66-eV emission band is associated with a S vacancy donor bound to a Tl vacancy acceptor that forms a VS-VTl Schottky pair. The photoconductivity spectra show the presence of a deep donor level located at 0.46 eV below the conduction-band edge, in good agreement with that measured by PL spectroscopy.
AB - Native defect levels in ternary compound Tl6I4S single crystals were studied by low-temperature photoluminescence (PL) and photoconductivity (PC) measurements. From the PL measurements, a broad emission band centered at 1.64 eV was observed at low temperatures. The peak can be decomposed using two standard Gaussian functions to reveal two emission bands at 1.55 and 1.66 eV. The PL peak at 1.55 eV is attributed to donor-acceptor pair recombination between a sulphur vacancy (VS) deep donor (Ed=0.57eV) and an antisite defect (SI) shallow acceptor (Ea=20meV). The 1.66-eV emission band is attributed to self-activated luminescence involving a defect complex and is described using a configuration coordinate model. Within this framework, the 1.66-eV emission band is associated with a S vacancy donor bound to a Tl vacancy acceptor that forms a VS-VTl Schottky pair. The photoconductivity spectra show the presence of a deep donor level located at 0.46 eV below the conduction-band edge, in good agreement with that measured by PL spectroscopy.
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U2 - 10.1103/PhysRevB.90.035205
DO - 10.1103/PhysRevB.90.035205
M3 - Article
AN - SCOPUS:84904677711
VL - 90
JO - Physical Review B-Condensed Matter
JF - Physical Review B-Condensed Matter
SN - 1098-0121
IS - 3
M1 - 035205
ER -