Non‐Layered Te/In2S3 Tunneling Heterojunctions with Ultrahigh Photoresponsivity and Fast Photoresponse

A photodetector based on 2D non‐layered materials can easily utilize the photogating effect to achieve considerable photogain, but at the cost of response speed. Here, a rationally designed tunneling heterojunction fabricated by vertical stacking of non‐layered In2S3 and Te flakes is studied systema...

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Bibliographic Details
Published in:Small (Weinheim an der Bergstrasse, Germany) Germany), 2022-05, Vol.18 (18), p.n/a
Main Authors: Cao, Xuanhao, Lei, Zehong, Huang, Baoquan, Wei, Aixiang, Tao, Lili, Yang, Yibin, Zheng, Zhaoqiang, Feng, Xing, Li, Jingbo, Zhao, Yu
Format: Article
Language:English
Subjects:
2D materials
Electric fields
Heterojunctions
Layered materials
Nanotechnology
photodetectors
Photoelectric effect
photogating effect
Photometers
Photovoltaic effect
Response time
tunneling heterojunctions
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Summary:A photodetector based on 2D non‐layered materials can easily utilize the photogating effect to achieve considerable photogain, but at the cost of response speed. Here, a rationally designed tunneling heterojunction fabricated by vertical stacking of non‐layered In2S3 and Te flakes is studied systematically. The Te/In2S3 heterojunctions possess type‐II band alignment and can transfer to type‐I or type‐III depending on the electric field applied, allowing for tunable tunneling of the photoinduced carriers. The Te/In2S3 tunneling heterojunction exhibits a reverse rectification ratio exceeding 104, an ultralow forward current of 10−12 A, and a current on/off ratio over 105. A photodetector based on the heterojunctions shows an ultrahigh photoresponsivity of 146 A W−1 in the visible range. Furthermore, the devices exhibit a response time of 5 ms, which is two and four orders of magnitude faster than that of its constituent In2S3 and Te. The simultaneously improved photocurrent and response speed are attributed to the direct tunneling of the photoinduced carriers, as well as a combined mechanism of photoconductive and photogating effects. In addition, the photodetector exhibits a clear photovoltaic effect, which can work in a self‐powered mode. Nonlayered Te/In2S3 tunneling heterojunctions possess type‐II band alignment and can transfer to type‐I or III depending on the electric field applied, exhibiting reverse rectification ratio exceeding 104 and ultralow forward current of 10−12 A. A photodetector based on heterojunctions shows greatly‐improved photoresponsivity of 146 A W−1 and response time of 5 ms compared to its constituent materials.
ISSN:1613-6810
1613-6829
DOI:10.1002/smll.202200445