异质结
材料科学
兴奋剂
光电探测器
光电子学
X射线光电子能谱
范德瓦尔斯力
激光器
费米能级
光电效应
光伏系统
光学
电子
物理
量子力学
核磁共振
生物
分子
生态学
作者
Jing Chen,Yabing Shan,Qiyuan Wang,Jingjing Zhu,Ran Liu
出处
期刊:Nanotechnology
[IOP Publishing]
日期:2020-05-01
卷期号:31 (29): 295201-295201
被引量:25
标识
DOI:10.1088/1361-6528/ab87cd
摘要
Van der Waals heterostructures (vdWHs) based on two-dimensional (2D) materials are being studied extensively for their prospective applications in photodetectors. As the pristine WSe2/MoTe2 heterostructure is a type I (straddling gap) structure, it cannot be used as a photovoltaic device theoretically, although both WSe2 and MoTe2 have excellent photoelectric properties. The Fermi level of p-doped WSe2 is close to its valence band. The p-doped WSe2/MoTe2 heterostructure can perform as a photovoltaic device because a built-in electric field appears at the interface between MoTe2 and p-doped WSe2. Here, a 633 nm laser was used for scanning the surface of WSe2 in order to obtain the p-doped WSe2. x-ray photoelectron spectroscopy (XPS) and electrical measurements verified that p-type doping in WSe2 is produced through laser treatment. The p-type doping in WSe2 includes substoichiometric WOx and nonstoichiometric WSex. A photovoltaic device using p-doped WSe2 and MoTe2 was successfully fabricated. The band structure, light-matter reactions, and carrier-transport in the p-doped WSe2/MoTe2 heterojunction were analyzed. The results showed that this photodetector has an on/off ratio of ≈104, dark current of ≈1 pA, and response time of 72 μs under the illumination of 633 nm laser at zero bias (Vds = 0 V). The proposed p-doping method may provide a new approach to improve the performance of nanoscale optoelectronic devices.
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