A large number of well-defined hexagonal etch pits is produced on the WSe2 surface by controlled anisotropic corrosion. As a result a mixed surface (combining both ⊥c and ||c components) is created. This surface exhibits photovoltaic properties even better than the atomically smooth van der Waals surface. Measurements of electron beam induced current performed at low temperatures give direct evidence for enhanced current collection of ||c facets. Observations made by transmission electron microscopy and scanning tunneling microscopy show the presence of very low ||c steps on the van der Waals surface.
Margulis, L.; Mahalu, D.; Parkinson, B.; and Tenne, R.
"Microscopy of Mixed Surfaces on Layered Semiconductors,"
Scanning Microscopy: Vol. 5
, Article 6.
Available at: https://digitalcommons.usu.edu/microscopy/vol5/iss4/6