Preparation of Bi2(Se0.53Te0.47)3 nanowires and their circular photogalvanic effect
Bi2(Se0.53Te0.47)3 nanowires were prepared by chemical vapor deposition,characterized by scanning electron microscopy and X-ray energy dispersive spectroscopy,and the circular photogalvanic effect(CPGE)of the samples were investigated.Using 1 064 nm laser excitation,the CPGE current is measured when the incident plane of laser is perpendicular to and parallel to the nanowires.The experi-mental results show that the measured CPGE current mainly comes from the topological surface states of the nanowires.The CPGE current is not zero when the laser vertically incident the nanowires,indicating that the CPGE current comes from the hexagonal warping effect of the energy band in nanowires.The CPGE current of the Bi2(Se0.53Te0.47)3 nanowires measured in this investigation is more than two times larger than that of the Bi2(Se0.23Te0.77)3 nanowires reported in literature.This is because the increase of Te component not only makes the Fermi level closer to the Dirac point,but also reduces the probability of carrier recombination in the nanowires.The two work together to increase the CPGE current.
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