Probing excitonic states in suspended two-dimensional semiconductors by photocurrent spectroscopy.

ABSTRACT: The optical response of semiconducting monolayer transition-metal dichalcogenides (TMDCs) is dominated by strongly bound excitons that are stable even at room temperature. However, substrate-related effects such as screening and disorder in currently available specimens mask many anticipated physical phenomena and limit device applications of TMDCs. Here, we demonstrate that that these undesirable effects are strongly suppressed in suspended devices. Extremely robust (photogain > 1,000) and fast (response time < 1 ms) photoresponse allow us to study, for the first time, the formation, binding energies, and dissociation mechanisms of excitons in TMDCs through photocurrent spectroscopy. By analyzing the spectral positions of peaks in the photocurrent and by comparing them with first-principl

SUBMITTER: Klots AR 

PROVIDER: S-EPMC4198869 | biostudies-literature | 2014 Oct

REPOSITORIES: biostudies-literature