Spontanous polarization induced photovoltaic effects in Van der Waals semiconductors
Different stackings in van der Waals materials offer a new opportunity to create and discover novel physical properties such as ferroelectricity. Recently we found a spontaneous polarization in a van der waals semiconductor with a stacking order that breaks the inversion symmetry. In a graphene contacted device, the spontaneous polarization induces a strong photovoltaic effect. The pv current is driven by the depolarization field and mainly composed of photo-excited electrons. Since the polarization is nearly uniform in the naturally existing bulk material, our observation provides a scalable way to utilize the emergent polarization in 2D materials.
The Univ. of British Columbia (Canada)