Andrey Krayev, AIST-NT Incorporated
Nanoscale Heterogeneities in Monolayer MoSe2 and WSe2 Revealed by Correlated SPM and TERS
Written by Natalie Briggs
The process of transferring few-layer, two-dimensional materials flakes is common in the study of intrinsic materials properties as well as the fabrication of heterostructures. While this process is widely acknowledged to be detrimental to materials quality, the exact effects or nature of materials damage is not well understood. Through the use of correlated scanning probe microscopy and tip-enhanced Raman spectroscopy (TERS), Andrey Krayev of AIST-NT Incorporated demonstrates that the correlation of these two techniques can clearly show defects in transferred flakes of monolayer MoSe2 and WSe2. For example, following layer transfer of MoSe2 flakes via NaOH, Krayev observes evidence of MoO3 incorporation in MoSe2 flakes resulting in possible p-doping and effects, and variation in exciton distribution and ratios within the flakes. Additionally, transferred flakes of WSe2 show formation of triangular holes following the transfer process, which are observed through correlation of friction and TERS mapping.