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Improving of the Rise and Decay Rates of an Ultraviolet Photodetector Using Stepwise Annealed ZnO Nanorods
Author(s) -
Kim Dongwan,
Leem JaeYoung
Publication year - 2019
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201800929
Subject(s) - nanorod , annealing (glass) , photoluminescence , materials science , exciton , ultraviolet , phosphor , emission intensity , recrystallization (geology) , optoelectronics , hydrothermal circulation , analytical chemistry (journal) , nanotechnology , chemical engineering , condensed matter physics , chemistry , metallurgy , paleontology , physics , chromatography , biology , engineering
ZnO nanorods (NRs) are grown on a ZnO seed layer using the hydrothermal method and subsequently annealed with increasing step of annealing from zero to three. The ZnO NRs without the annealing have the longest length and diameter, and it is decreased with increasing step of annealing, owing to the recrystallization during step‐annealing. The ZnO NRs step‐annealed for three times exhibit the highest intensity of the near‐band‐edge (NBE) emission, whereas ZnO NRs without annealing have the lowest intensity of NBE emission. With respect to the deep‐level (DL) emissions, broad yellow and green emissions are observed, and the intensity of DL emission decreases with increasing step of annealing. Further, the low‐temperature photoluminescence spectrum measured at 12 K of the ZnO nanorods step‐annealed for three times contains a donor‐bound exciton (D°X) emission, as well as emissions related to the donor–acceptor pair (DAP) transition and the first‐order and second‐order longitudinal optical phonon replicas of DAP transition. Finally, with respect to the photoresponse, the ZnO NRs step‐annealed for three times exhibit the fastest rise and decay rates compared with the other NRs.