@article{Zeng2022, 
author = {Peiyu Zeng and Wenhui Wang and Jie Jiang and Zheng Liu and Dongshuang Han and Shuojie Hu and Jiaoyan He and Peng Zheng and Hui Zheng and Liang Zheng and Xiaojing Yao and Weitao Su and Dexuan Huo and Zhangting Wu and Zhenhua Ni and Yang Zhang},
title = {Thickness-dependent enhanced optoelectronic performance of surface charge transfer-doped ReS2 photodetectors},
year = {2022},
journal = {Nano Research},
volume = {15},
number = {4},
pages = {3638-3646},
keywords = {Surface charge transfer doping, ReS2, thickness, response time, responsivity, tetrafluorotetracyanoquinodimethane (F4-TCNQ)},
url = {https://www.sciopen.com/article/10.1007/s12274-021-3954-2},
doi = {10.1007/s12274-021-3954-2},
abstract = {Surface charge transfer doping has been widely utilized to tune the electronic and optical properties of semiconductor photodetectors based on low-dimensional materials. Although many studies have been conducted on the performance (response time, responsivity, etc.) of doped photodetectors and their mechanisms, they merely examined a specific thickness and did not systematically explore the dependence of doping effects on the number of layers. This work performs a series of investigations on ReS2 photodetectors with different numbers of layers and demonstrates that the p-dopant tetrafluorotetracyanoquinodimethane (F4-TCNQ) converts the deep trap states into recombination centers for few-layer ReS2 and induces a vertical p-n junction for thicker ReS2. A response time of 200 ms is observed in the decorated 2-layer ReS2 photodetector, more than two orders of magnitude faster than the response of the pristine photodetector, due to the disappearance of deep trap states. A current rectification ratio of 30 in the F4-TCNQ-decorated sandwiched ReS2 device demonstrates the formation of a vertical p-n junction in a thicker ReS2 device. The responsivity is as high as 2,000 A/W owing to the strong carrier separation of the p-n junction. Different thicknesses of ReS2 enable switching of the prominent operating mechanism between transforming deep trap states into recombination centers and forming a vertical p-n junction. The thickness-dependent doping effect of a two-dimensional material serves as a new mechanism and provides a scheme toward improving the performance of other semiconductor devices, especially optical and electronic devices based on low-dimensional materials.}
}