Jul 28, 2017

Researchers from the US, Japan and Korea report an efficient generation of microsecond-long-lived valley polarization in WSe2/MoS2 heterostructures by exploiting the ultrafast charge transfer processes in the heterostructure that efficiently creates resident holes in the WSe2 layer.

 Ultrafast charge transfer process in the WSe2/MoS2 heterostructure

The researchers say that the valley-polarized holes exhibit near-unity valley polarization and ultralong valley lifetime. The researchers observed a valley-polarized hole population lifetime of more than 1 μs and a valley depolarization lifetime of more than 40 μs at 10 K. The researchers say that near-perfect generation of valley-polarized holes combined with the ultralong valley lifetime may open up new opportunities for novel valleytronics and spintronics applications.