Open AccessTime-resolved photoluminescence of Te isoelectronic center in ZnS
Author(s) -
Xiaoxuan Yang,
Zhijun Xu,
Luo Xiang-dong,
Fang Zai-Li,
Guohua Li,
Su Yin-Qiang,
Weikun Ge
Publication year - 2005
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.54.2272
Subject(s) - exciton , photoluminescence , nanosecond , recombination , ternary operation , atomic physics , materials science , valence band , binding energy , valence (chemistry) , molecular physics , condensed matter physics , chemistry , physics , band gap , optoelectronics , optics , laser , biochemistry , organic chemistry , computer science , gene , programming language
The recombination dynamics of localized exciton in ZnS1-xTex ternary alloys has been investigated by time-resolved photoluminescence (PL) in a large Te concentration range from 0005 to 085. It is found that the radiativ e recombination lifetimes of different Te isoelectronic centers show a significa nt difference, varying from a few nanoseconds to tens of nanosecond. The lifetim e reaches a maximum of 40 ns in the sample of x=015. The present result s could be understood in terms of the exciton localization effect. When the Te c oncentration is small, the Te isoelectronic centers evolve gradually from a sing le Te impurity (Te1) to the Te clusters (Ten). The exciton localization is enhanced, resulting in the increase of exciton recombination lifetime. When t he Te concentration is further increased, the Te clusters (Ten) becom e lar ge enough to hybridize the Te localized states and the host valence band states. Therefore, the excitons bound to Te isoelectronic centers become more or less d elocalized, resulting in a shorter lifetime. Furthermore, the concentration depe ndence of the exciton binding energy and the PL intensity variation with tempera ture have been mearsured. The results further confirm the above conclusion.