2D Materials: Molybdenum disulfide
Though molybdenum disulfide (MoS2) is also used in bulk form, it is perhaps the most well known two-dimensional transition metal dichalcogenide. As a bulk material its most common application is likely that of a solid state lubricant, but when MoS2 is produced in monolayer form it transitions from an indirect bandgap semiconductor to a direct bandbap semiconductor.
This transition in its properties – specifically its usage as a semiconductor – is what makes MoS2 stand apart from other common 2D materials such as graphene. Because of it’s structure (see the image above), monolayers of MoS2 are still three atoms thick, not quite as thin as flatter structures such as graphene. MoS2 is commonly produced through exfoliation.
Current applications of mono- or multi-layer MoS2 include field effect transistors, memresistors, electrolysis, and photovoltaics and photodetectors. However, it is still a relatively new material and applications are limited by the difficultly in dealing with such small materials.