Abstract
Abstract Understanding the dissociation of excitons into long-lived free charge carriers is a crucial issue when considering the applications of transition metal dichalcogenides (excitonic semiconductors) oriented toward the use of solar energy (such as photovoltaics or photocatalysis). In our work, long-lived carriers have been observed by time-resolved microwave photoconductivity (TRMC) for the first time in both atomically thin and bulk MoS2, MoSe2, WS2, and WSe2 crystals. The lifetime of majority carriers is close to microseconds and can even reach several microseconds due to different contribution of surface and defect states, as well as surface band bending (bulk). The three components depend on the material and vary from sample to sample, therefore determining the dynamics of the TRMC signal. The rise time of TRMC signal was found to be in the range of 0.1–0.2 μs and as it depends on the studied material it can be speculated that it is related to the dissociation time of excitons captured by traps.
Highlights
Transition metal dichalcogenides (TMDs) such as MX2 (M = Mo, W; X = S, Se) belong to the exciting class of layered materials of unprecedented physiochemical properties
timeresolved microwave photoconductivity (TRMC) has been applied for the first time to study carrier dynamics in both atomically thin and bulk MoS2, MoSe2, WS2, and WSe2 crystals
The three components determine the dynamics of the TRMC signal as confirmed by TRMC study of monolayer and bulk TMDs as well as bulk TMDs with various doping and different band bending
Summary
Transition metal dichalcogenides (TMDs) such as MX2 (M = Mo, W; X = S, Se) belong to the exciting class of layered materials of unprecedented physiochemical properties. The latter make them perfect candidates for applications in sustainable technologies of tomorrow such as inter alia (opto)electronics ( photovoltaics) and solardriven chemistry (artificial photosynthesis, photocatalysis) [1,2,3,4,5,6,7]. When a bulk TMD is thinned down to a monolayer, both its electronic and optical properties change [8,9,10,11,12]. In the case of their bulk counterparts, the issue of charge carrier dynamics has not been studied comprehensively [35] most likely due to the lack of photoluminescence
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
