Cao Xuanhao, Lei Zehong, Huang Baoquan, Wei Aixiang, Tao Lili, Yang Yibin, Zheng Zhaoqiang, Feng Xing, Li Jingbo, Zhao Yu
Guangdong Provincial Key Laboratory of Information Photonics Technology, Guangdong Provincial Key Laboratory of Functional Soft Condensed Matter, School of Material and Energy, Guangdong University of Technology, Guangzhou, 510006, China.
Guangdong Provincial Key Laboratory of Chip and Integration Technology, Institute of Semiconductors, South China Normal University, Guangzhou, 510631, China.
Small. 2022 May;18(18):e2200445. doi: 10.1002/smll.202200445. Epub 2022 Apr 3.
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 In S and Te flakes is studied systematically. The Te/In S 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/In S tunneling heterojunction exhibits a reverse rectification ratio exceeding 10 , an ultralow forward current of 10 A, and a current on/off ratio over 10 . A photodetector based on the heterojunctions shows an ultrahigh photoresponsivity of 146 A W 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 In S 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.
基于二维非层状材料的光电探测器能够轻松利用光闸效应实现可观的光增益，但代价是响应速度。在此，对通过垂直堆叠非层状In S和Te薄片制造的经过合理设计的隧道异质结进行了系统研究。Te/In S异质结具有II型能带排列，并且根据所施加的电场可转变为I型或III型，从而实现光生载流子的可调谐隧穿。Te/In S隧道异质结呈现出超过10的反向整流比、10 A的超低正向电流以及超过10的电流开/关比。基于该异质结的光电探测器在可见光范围内显示出146 A W的超高光响应率。此外，这些器件的响应时间为5 ms，比其组成部分In S和Te快两个和四个数量级。光电流和响应速度的同时提高归因于光生载流子的直接隧穿以及光电导和光闸效应的组合机制。此外，该光电探测器表现出明显的光伏效应，能够以自供电模式工作。
