期刊
ACS APPLIED MATERIALS & INTERFACES
卷 12, 期 13, 页码 15034-15042出版社
AMER CHEMICAL SOC
DOI: 10.1021/acsami.9b21230
关键词
transition metal dichakogenides (TMDs); scanning photocurrent microscopy; photo-electrochemistry; single nanosheet; photoluminescence mapping; Raman mapping
资金
- Air Force Office of Scientific Research (AFOSR) [FA9550-17-1-0255]
Substrates influence the electrical and optical properties of monolayer (ML) MoS2 in field-effect transistors and photodetectors. Photoluminescence (PL) and Raman spectroscopy measurements have shown that conducting substrates can vary the doping concentration and influence exciton decay channels in ML-MoS2. Doping and exciton decay dynamics are expected to play a major role in the efficiency of light-driven chemical reactions, but it is unclear to what extent these factors contribute to the photo(electro)catalytic properties of ML-MoS2. Here, we report spatially resolved PL, Raman, and photoelectrochemical current measurements of 5-10 mu m-wide ML-MoS2 triangles deposited on pairs of indium-doped tin oxide (ITO) electrodes that are separated by a narrow insulating quartz channel [i.e., an ITO interdigitated array (IDA) electrode]. Optical microscopy images and atomic force microscopy measurements revealed that the ML-MoS2 triangles lie conformally on the quartz and ITO substrates. The PL spectrum of MoS2 shifts and decreases in intensity in the ITO region, which can be attributed to differences in nonradiative and radiative exciton decay channels. Raman spectra showed no significant peak shifts on the two substrates that would have indicated a substrate-induced doping effect. We spatially resolved the photo-electrochemical current because of hole-induced iodide oxidation and observed that ML-MoS2 produces lower photocurrents in the quartz region than in the ITO region. The correlated PL, Raman, and photocurrent mapping data show that the MoS2/quartz interface diminishes fast nonradiative exciton decay pathways but the photocurrent response in the quartz region is likely limited by inefficient in-plane carrier transport to the ITO electrode because of carrier recombination with S vacancies in MoS2 or charged impurities in the quartz substrate. Nonetheless, the experimental methodology presented herein provides a framework to evaluate substrate engineering strategies to tune the (photo)electrocatalytic properties of two-dimensional materials.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据