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Photoresponse Properties of CdSe Single‐Nanoribbon Photodetectors
Author(s) -
Jiang Y.,
Zhang W. J.,
Jie J. S.,
Meng X. M.,
Fan X.,
Lee S.T.
Publication year - 2007
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200600351
Subject(s) - materials science , photocurrent , photodetector , optoelectronics , band gap , wavelength , dark current , ribbon , photoconductivity , photodiode , light intensity , optics , composite material , physics
Photodetectors are fabricated from individual single‐crystal CdSe nanoribbons, and the photoresponse properties of the devices are studied systematically. The photodetector shows a high sensitivity towards excitation wavelength with a sharp cut‐off at 710 nm, corresponding to the bandgap of CdSe. The device exhibits a high photo‐to‐dark current ratio of five orders of magnitude at 650 nm, and can function with excellent stability, reproducibility, and high response speed (< 1 ms) in a wide range of switching frequency (up to 300 Hz). The photocurrent of the device shows a power‐law dependence on light intensity. This finding together with the analysis of the light intensity‐dependent response speed reveals the existence of various traps at different energy levels (shallow and deep) in the bandgap. Coating with a thin SiO 2 isolating layer increases the photocurrent but decreases the response speed of the CdSe nanoribbon, which is attributed to reduction of recombination centers on ribbon surface.