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ZnO‐based photodetector with internal photocurrent gain
Author(s) -
Kosyachenko L. A.,
Lashkarev G. V.,
Sklyarchuk V. M.,
Ievtushenko A. I.,
Sklyarchuk O. F.,
Lazorenko V. I.,
Ulyashin A.
Publication year - 2010
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.200925443
Subject(s) - photocurrent , materials science , heterojunction , optoelectronics , photodiode , schottky diode , photodetector , schottky barrier , sputter deposition , common emitter , quantum efficiency , sensitivity (control systems) , evaporation , sputtering , anode , photoconductivity , thin film , electrode , diode , nanotechnology , electronic engineering , chemistry , physics , engineering , thermodynamics
The photoresponsive structures prepared by magnetron sputtering of ZnO on p‐Si substrates followed by vacuum evaporation of semitransparent Ni film on ZnO surface are investigated. The obtained Ni/n‐ZnO/p‐Si structures show high sensitivity that sharply increases with increase in applied voltage. Under a bias voltage of 5 V, the responsivities at λ = 390 nm and λ = 850 nm were equal to 210 and 110 A/W, which correspond to quantum efficiencies of 655 and 165, respectively. It is assumed that the observed strong response is attributed to internal gain in the Ni/n‐ZnO/p‐Si phototransistor structure containing Ni/n‐ZnO Schottky contact as the emitter junction and n‐ZnO/p‐Si heterostructure as the collector junction. The response time of the device is ∼10 –7 s. Alternative mechanisms of photocurrent multiplication in such structures are also discussed.