Indirect Band Gap in Scrolled MoS Monolayers.

MoS nanoscrolls that have inner core radii of ∼250 nm are generated from MoS monolayers, and the optical and transport band gaps of the nanoscrolls are investigated. Photoluminescence spectroscopy reveals that a MoS monolayer, originally a direct gap semiconductor (∼1.85 eV (optical)), changes into an indirect gap semiconductor (∼1.