Electronic Structure of Black Phosphorus in Self-Consistent Pseudopotential Approach

Asahina, Hideo; Shindo, Koichi; Morita, Akira

doi:10.1143/jpsj.51.1193

Cited by 151 publications

(87 citation statements)

References 8 publications

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“…2a) is determined to be À 8°. The anisotropy in the optical conductivity arises from the directional dependence of the interband transition matrix elements in anisotropic BP bands 36,43 .…”

Section: Resultsmentioning

confidence: 99%

Rediscovering black phosphorus as an anisotropic layered material for optoelectronics and electronics

2014

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Graphene and transition metal dichalcogenides (TMDCs) are the two major types of layered materials under intensive investigation. However, the zero-bandgap nature of graphene and the relatively low mobility in TMDCs limit their applications. Here we reintroduce black phosphorus (BP), the most stable allotrope of phosphorus with strong intrinsic in-plane anisotropy, to the layered-material family. For 15-nm-thick BP, we measure a Hall mobility of 1,000 and 600 cm 2 V À 1 s À 1 for holes along the light (x) and heavy (y) effective mass directions at 120 K. BP thin films also exhibit large and anisotropic in-plane optical conductivity from 2 to 5 mm. Field-effect transistors using 5 nm BP along x direction exhibit an on-off current ratio exceeding 10 5 , a field-effect mobility of 205 cm 2 V À 1 s À 1 , and good current saturation characteristics all at room temperature. BP shows great potential for thin-film electronics, infrared optoelectronics and novel devices in which anisotropic properties are desirable.

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Section: Resultsmentioning

confidence: 99%

Rediscovering black phosphorus as an anisotropic layered material for optoelectronics and electronics

2014

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“…[34][35][36] From band structure calculation, it can be seen that for both the electron and the hole, the effective mass in the x-y plane is fairly large. The effective mass in the x-direction is lightest, and that in the layer-stacking z direction is lighter than that in the in-plane y-direction due to the van der Waals Magnetoresistance was also studied in these samples down to 0.5 K in temperature and up to 6 T in magnetic fields, and 2D Anderson localization was also observed.…”

Section: Electrical Conduction and Carrier Mobilitymentioning

confidence: 99%

Semiconducting black phosphorus: synthesis, transport properties and electronic applications

et al. 2015

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“…For few-layer phosphorene, interlayer interactions reduce the band gap for each layer 3 added, and eventually reach ~ 0.3 eV (refs 8-11) for bulk black phosphorus. The direct gap also moves to the Z point as a consequence 7,12 . Such a band structure provides a much needed gap for the field-effect transistor (FET) application of two dimensional (2D) materials such as graphene, and the thickness-dependent direct band gap may lead to potential applications in optoelectronics, especially in the infrared regime.…”

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confidence: 99%

Black phosphorus field-effect transistors

et al. 2014

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Black phosphorus is a layered material in which individual atomic layers are stacked together by Van der Waals interactions, much like bulk graphite 1 . Inside a single layer, each phosphorus atom is covalently bonded with three adjacent phosphorus atoms to form a puckered honeycomb structure [2][3][4] (Fig. 1a). The three bonds take up all three valence electrons of phosphorus, so unlike graphene 5,6 a monolayer black phosphorus (termed "phosphorene") is a semiconductor with a predicted direct band gap of ~ 2 eV at the Γ point of the first Brillouin zone 7 . For few-layer phosphorene, interlayer interactions reduce the band gap for each layer 3 added, and eventually reach ~ 0.3 eV (refs 8-11) for bulk black phosphorus. The direct gap also moves to the Z point as a consequence 7,12 . Such a band structure provides a much needed gap for the field-effect transistor (FET) application of two dimensional (2D) materials such as graphene, and the thickness-dependent direct band gap may lead to potential applications in optoelectronics, especially in the infrared regime. In addition, observations of phase transition from semiconductor to metal 13,14 and superconductor under high pressure 15,16 We next fabricate few-layer phosphorene FETs with a back-gate electrode (see Fig. 2a). A scotch tape based mechanical exfoliation method is employed to peel thin flakes from bulk crystal onto degenerately doped silicon wafer covered with a layer of thermally grown silicon dioxide. Optical microscopy and atomic force microscopy (AFM) are used to hunt thin flake samples and determine their thickness (Fig. 2a). The switching behaviour of our few-layer phosphorene transistor at room temperature is characterized in vacuum (~ 10 -6 mBar), in a configuration depicted in -30 V to 0 V, the channel switches from "on" state to "off" state, and a drop in drain current by a factor of ~ 10 5 is observed. The measured drain current modulation is 4 orders of magnitude larger than that in graphene (due to its lack of bandgap), and 5 approaches the value recently reported in MoS2 devices 17 . Such a high drain current modulation makes black phosphorus thin film a promising material for applications in digital electronics 22 . Similar switching behaviour (with varying drain current modulation) is observed on all black phosphorous thin film transistors with thicknesses up to 50 nm. We note that the "on" state current of our devices has not yet reached saturation, due to the fact that the doping level is limited by the break-down electric field of the SiO2 back-gate dielectric. It is therefore possible to achieve even higher drain current modulation by using high-k materials as gate dielectrics for higher doping. Meanwhile, a subthreshold swing (SS) of ~ 5 V/decade is observed, which is much larger than the SS in commercial Si-based devices (~ 70 mV/decade).We note that the SS in our devices varies from sample to sample (from ~ 3.7 V/decade to ~ 13.3 V/decade), and is on the same order of magnitude as reported in multilayerMoS2 devices with a simila...

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Electronic Structure of Black Phosphorus in Self-Consistent Pseudopotential Approach

Cited by 151 publications

References 8 publications

Rediscovering black phosphorus as an anisotropic layered material for optoelectronics and electronics

Rediscovering black phosphorus as an anisotropic layered material for optoelectronics and electronics

Semiconducting black phosphorus: synthesis, transport properties and electronic applications

Black phosphorus field-effect transistors

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