Schottky Barriers in Bilayer Phosphorene Transistors.
It is unreliable to evaluate the Schottky barrier height (SBH) in monolayer (ML) 2D material field effect transistors (FETs) with strongly interacted electrode from the work function approximation (WFA) because of existence of the Fermi-level pinning. Here, we report the first systematical study of bilayer (BL) phosphorene FETs in contact with a series of metals with a wide work function range (Al, Ag, Cu, Au, Cr, Ti, Ni, and Pd) by using both ab initio electronic band calculations and quantum transport simulation (QTS). Different from only one type of Schottky barrier (SB) identified in the ML phosphorene FETs, two types of SBs are identified in BL phosphorene FETs: the vertical SB between the metallized and the intact phosphorene layer, whose height is determined from the energy band analysis (EBA); the lateral SB between the metallized and the channel BL phosphorene, whose height is determined from the QTS. The vertical SBHs show a better consistency with the lateral SBHs of the ML phosphorene FETs from the QTS compared than that of the popular WFA. Therefore, we develop a better and more general method than the WFA to estimate the lateral SBHs of ML semiconductor transistors with strongly interacted electrodes based on the EBA for its BL counterpart. In terms of the QTS, n-type lateral Schottky contacts are formed between BL phosphorene and Cr, Al, and Cu electrodes with electron SBH of 0.27, 0.31, and 0.32 eV, respectively, while p-type lateral Schottky contacts are formed between BL phosphorene and Pd, Ti, Ni, Ag, and Au electrodes with hole SBH of 0.11, 0.18, 0.19, 0.20, and 0.21 eV, respectively. The theoretical polarity and SBHs are in good agreement with available experiments. Our study provides an insight into the BL phosphorene-metal interfaces that are crucial for designing the BL phosphorene device.
State Key Laboratory of Mesoscopic Physics and Department of Physics, Peking University , Beijing 100871, P. R. China.
Yuanyuan
http://orcid.org/0000-0002-0654-3677
Y
Pan
State Key Laboratory of Mesoscopic Physics and Department of Physics, Peking University , Beijing 100871, P. R. China.
Yang
Y
Dan
Nanophotonics and Optoelectronics Research Center, Qian Xuesen Laboratory of Space Technology, China Academy of Space Technology , Beijing 100094, P. R. China.
Yangyang
http://orcid.org/0000-0003-3992-3796
Y
Wang
State Key Laboratory of Mesoscopic Physics and Department of Physics, Peking University , Beijing 100871, P. R. China.
Meng
M
Ye
State Key Laboratory of Mesoscopic Physics and Department of Physics, Peking University , Beijing 100871, P. R. China.
Han
http://orcid.org/0000-0002-1483-5899
H
Zhang
State Key Laboratory of Information Photonics and Optical Communications & School of Science, Beijing University of Posts and Telecommunications , Beijing 100876, P. R. China.
Ruge
http://orcid.org/0000-0001-8991-8640
R
Quhe
State Key Laboratory of Mesoscopic Physics and Department of Physics, Peking University , Beijing 100871, P. R. China.
Xiuying
http://orcid.org/0000-0002-7393-9567
X
Zhang
State Key Laboratory of Mesoscopic Physics and Department of Physics, Peking University , Beijing 100871, P. R. China.
Jingzhen
J
Li
Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of Education , Beijing 100876, P. R. China.
Wanlin
W
Guo
Department of Physics, Washington University in St. Louis , St. Louis, Missouri 63130, United States.
Li
L
Yang
State Key Laboratory of Mesoscopic Physics and Department of Physics, Peking University , Beijing 100871, P. R. China.|Collaborative Innovation Center of Quantum Matter , Beijing 100871, P. R. China.
Jing
J
Lu
Schottky barrier; bilayer phosphorene transistor; energy band; interface; quantum transport simulation