Tunneling Phototransistor-A Route Towards Fast Photodetection with High Gain
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AbstractPhotodetectors based on two-dimensional materials, which provide scalable active interfaces, high performance in photoresponse, high flexibility, etc., have aroused huge attention. Particularly, graphene hybrid phototransistors, which are composed of a graphene sheet as carrier transport channel and an efficient light absorption material as photo-active layer, highly likely give rise to their giant photoconductive gains. However, their response speeds are dramatically compromised at the expense due to the large number of trap states at the interfaces.
Herein, by intercalating a large-area atomically thin MoS2 film into a graphene/silicon vertical junction, we have developed a prototype tunneling phototransistor, which exhibits a record-fast response (within 30 ns) and a high responsivity (~3×10^4 A/W at 635 nm illumination) across visible to the near infrared spectral range (400 nm-1100 nm). The bulk silicon serves as an optical active layer and the MoS2 film acts as a passivation layer for reducing surface states and offering an ultra-thin layer for the carrier tunneling. Photo-excited carrier transfer process driven by the ultra-fast quantum tunneling effect rather than by the carrier drift in the depletion region enables a superior response speed, while the responsivity retains high. The carrier tunneling process is systematically investigated in terms of its dependences on the built-in field, the tunneling layer thickness and temperature. This intriguing tunneling phototransistor with both high speed and high responsivity, as well as with large photo active area, offers significant potential in practical applications among existing integrated optoelectronic devices.
All Author(s) ListLi Tao, Zefeng Chen, Xinming Li, Jian-bin Xu
Name of Conference2016 MRS Fall Meeting & Exhibit
Start Date of Conference27/11/2016
End Date of Conference02/12/2016
Place of ConferenceBoston, MA
Country/Region of ConferenceUnited States of America
LanguagesEnglish-United States
KeywordsGraphene, Passivation, Photoconductivity

Last updated on 2018-21-01 at 21:39