Searching electrode material with vanishing Schottky barrier for Blue Phosphorene by high-throughput calculations

Hefei Wang, Chen Si, Jian Zhou, Zhimei Sun^*

ABSTRACT

An appropriate electrode material is crucial for two-dimensional (2D) semiconductors, where a vanishing Schottky barrier is ideal but is a great challenge. Here, using Blue phosphorene as an example, which is a promising 2D semiconductor for electronic and optoelectronic applications, we provide design role of searching optimal electrode materials with vanishing Schottky barrier within a family of 2D transition metal carbides (MXenes) based on high-throughput ab initio calculations.   Our results show that Zr-, Hf- and Nb-based MXenes are ideal electrode materials for BlueP based on extensive investigations of the electronic properties and interfacial Schottky barrier characteristics of BlueP/MXene heterojunctions. Yet the strong interaction between BlueP and bare MXenes destroy the semiconducting character of BlueP, and thus bare MXenes are not ideal contact electrodes. While with surface functionalization of MXene, the intrinsic electronic feature of BlueP is well preserved in the BlueP/surface-engineered MXene heterojunctions. Furthermore, the interfacial Schottky barriers of the heterojunctions are affected by the terminal surface groups on MXenes and vanishing Schottky barriers are achieved in some MXenes with the formula Zr_n+1C_nF₂, Hf_n+1C_nF₂, Zr_n+1C_n(OH)₂, Hf_n+1C_n(OH)₂ and Nb_n+1C_n(OH)₂. Finally, we demonstrate that the work functions of MXenes and the interface dipole induced by charge rearrangement are two underlying factors to determine the magnitude of Schottky barriers. This work provides fundamentals for selecting ideal electrode material for BlueP and is also benefit for optimizing electrodes for other 2D semiconductors.

      DOI：10.12110/firstfmge.20171121.104