First-principles study on electronic states of In2Se3/Au heterostructure controlled by strain engineering.

ABSTRACT

The development of low-dimensional multifunctional devices has become increasingly important as the size of field-effect transistors decreases. In recent years, the two-dimensional (2D) semiconductor In2Se3 has emerged as a promising candidate for applications in the fields of electronics and optoelectronics owing to its remarkable spontaneous polarization properties. Through first-principles calculations, the effects of the polarization direction and biaxial tensile strain on the electronic and contact properties of In2Se3/Au heterostructures are investigated. The contact type of In2Se3/Au heterostructures depends on the polarization direction of In2Se3. The more charge transfers from the metal to the space charge region, the biaxial tensile strain increases. Moreover, the upward polarized In2Se3 in contact with Au maintains a constant n-type Schottky contact as the biaxial tensile strain increases, with a barrier height Φ SB,n of only 0.086 eV at 6% strain, which is close to ohmic contact. On the other hand, the downward polarized In2Se3 in contact with Au can be transformed from p-type to n-type by applying a biaxial tensile strain. Our calculation results can provide a reference for the design and fabrication of In2Se3-based field effect transistors.