Ji-Hwan Baek1,Seong Chul Hong1,Yeon Ho Kim2,Yeonjoon Jung1,Chul-Ho Lee2,Gwan-Hyong Lee1
Seoul National University1,Korea University2
Ji-Hwan Baek1,Seong Chul Hong1,Yeon Ho Kim2,Yeonjoon Jung1,Chul-Ho Lee2,Gwan-Hyong Lee1
Seoul National University1,Korea University2
Recently, the ferroelectric property in bilayer rhombohedral phase (3R) transition metal dichalcogenides (TMDs) bilayers was reported both theoretically and experimentally due to the inversion symmetry breaking, while the net electrical polarization in the 2H phase is zero due to the presence of the inversion symmetry. The spontaneous electrical polarization direction of 3R-TMDs is determined by a stacking sequence of metal (M) and chalcogen (X) atoms, XM- or MX- stacking, where every X atom on the top layer is located over the M atoms on the bottom layer in the XM stacking and vice versa. Not only the ferroelectricity but a bulk photovoltaic effect can be induced from this intrinsic polarization in 3R TMDs bilayers without built-in potential. Here we fabricated 3R TMDs bilayers devices with near-zero twist angle which have triangular domains of the XM and MX stacking are formed alternately, and an area of those domains can be modulated by applying external out-of-plane electric field, because the stacking sequence of M and X atoms are aligned along the direction of the external electric field. As a result, the opposite direction of photocurrent was obtained by changing the sign of the applied gate voltage.