title: Effect of multilayer structure, stacking order and external electric field on the electrical properties of few-layer boron-phosphide.
abstract: Development of nanoelectronics requires two-dimensional (2D) systems with both direct-bandgap and tunable electronic properties as they act in response to the external electric field (E-field). Here, we present a detailed theoretical investigation to predict the effect of atomic structure, stacking order and external electric field on the electrical properties of few-layer boron-phosphide (BP). We demonstrate that the splitting of bands and bandgap of BP depends on the number of layers and the stacking order. The values for the bandgap show a monotonically decreasing relationship with increasing layer number. We also show that AB-stacking BP has a direct-bandgap, while ABA-stacking BP has an indirect-bandgap when the number of layers n > 2. In addition, for a bilayer and a trilayer, the bandgap increases (decreases) as the electric field increases along the positive direction of the external electric field (E-field) (negative direction). In the case of four-layer BP, the bandgap exhibits a nonlinearly decreasing behavior as the increase in the electric field is independent of the electric field direction. The tunable mechanism of the bandgap can be attributed to a giant Stark effect. Interestingly, the investigation also shows that a semiconductor-to-metal transition may occur for the four-layer case or more layers beyond the critical electric field. Our findings may inspire more efforts in fabricating new nanoelectronics devices based on few-layer BP.
authors.affiliation: Faculty of Electromechanical Engineering, Guilin University of Electronic Technology, 541004 Guilin, China. xianpingchen1979@126.com.
authors.forename: Xianping
authors.initials: X
authors.lastname: Chen
authors.forename: Chunjian
authors.initials: C
authors.lastname: Tan
authors.forename: Qun
authors.initials: Q
authors.lastname: Yang
authors.forename: Ruishen
authors.initials: R
authors.lastname: Meng
authors.forename: Qiuhua
authors.initials: Q
authors.lastname: Liang
authors.forename: Junke
authors.initials: J
authors.lastname: Jiang
authors.forename: Xiang
authors.initials: X
authors.lastname: Sun
authors.forename: D Q
authors.initials: DQ
authors.lastname: Yang
authors.forename: Tianling
authors.initials: T
authors.lastname: Ren