Direct observation of the layer-dependent electronic structure in phosphorene.

Phosphorene, a single atomic layer of black phosphorus, has recently emerged as a new two-dimensional (2D) material that holds promise for electronic and photonic technologies. Here we experimentally demonstrate that the electronic structure of few-layer phosphorene varies significantly with the number of layers, in good agreement with theoretical predictions. The interband optical transitions cover a wide, technologically important spectral range from the visible to the mid-infrared. In addition, we observe strong photoluminescence in few-layer phosphorene at energies that closely match the absorption edge, indicating that they are direct bandgap semiconductors. The strongly layer-dependent electronic structure of phosphorene, in combination with its high electrical mobility, gives it distinct advantages over other 2D materials in electronic and opto-electronic applications.

[1]  A. Morita,et al.  Electronic Structure of Black Phosphorus in Self-Consistent Pseudopotential Approach , 1982 .

[2]  K. L. Shepard,et al.  Hofstadter’s butterfly and the fractal quantum Hall effect in moiré superlattices , 2013, Nature.

[3]  F. Xia,et al.  Tunable optical properties of multilayer black phosphorus thin films , 2014, 1404.4030.

[4]  Jie Shan,et al.  Strongly enhanced charge-density-wave order in monolayer NbSe2. , 2015, Nature nanotechnology.

[5]  H. Grubin.  The physics of semiconductor devices , 1979, IEEE Journal of Quantum Electronics.

[6]  P. Kim,et al.  Experimental observation of the quantum Hall effect and Berry's phase in graphene , 2005, Nature.

[7]  K. L. Shepard,et al.  One-Dimensional Electrical Contact to a Two-Dimensional Material , 2013, Science.

[8]  Wei Ji,et al.  High-mobility transport anisotropy and linear dichroism in few-layer black phosphorus , 2014, Nature communications.

[9]  Pablo Jarillo-Herrero,et al.  Two-dimensional crystals: phosphorus joins the family. , 2014, Nature nanotechnology.

[10]  M. Cardona,et al.  Fundamentals of semiconductors : physics and materials properties , 1997 .

[11]  Yang,et al.  Origin of the Stokes shift: A geometrical model of exciton spectra in 2D semiconductors. , 1993, Physical review letters.

[12]  F. Xia,et al.  Rediscovering black phosphorus as an anisotropic layered material for optoelectronics and electronics. , 2014, Nature communications.

[13]  R. Hultgren,et al.  The Atomic Distribution in Red and Black Phosphorus and the Crystal Structure of Black Phosphorus , 1935 .

[14]  Wei Ruan,et al.  Giant bandgap renormalization and excitonic effects in a monolayer transition metal dichalcogenide semiconductor. , 2014, Nature materials.

[15]  P. Y. Yu,et al.  Fundamentals of Semiconductors , 1995 .

[16]  A. Geim,et al.  Two-dimensional gas of massless Dirac fermions in graphene , 2005, Nature.

[17]  R. Soklaski,et al.  Layer-controlled band gap and anisotropic excitons in few-layer black phosphorus , 2014 .

[18]  A. H. Castro Neto,et al.  Electric field effect in ultrathin black phosphorus , 2014 .

[19]  Wang Yao,et al.  Spin and pseudospins in layered transition metal dichalcogenides , 2014, Nature Physics.

[20]  T. Taniguchi,et al.  Massive Dirac Fermions and Hofstadter Butterfly in a van der Waals Heterostructure , 2013, Science.

[21]  S. Sze,et al.  Physics of Semiconductor Devices: Sze/Physics , 2006 .

[22]  Louie,et al.  Electron correlation in semiconductors and insulators: Band gaps and quasiparticle energies. , 1986, Physical review. B, Condensed matter.

[23]  Zongfu Yu,et al.  Extraordinary photoluminescence and strong temperature/angle-dependent Raman responses in few-layer phosphorene. , 2014, ACS nano.

[24]  Yuerui Lu,et al.  Optical tuning of exciton and trion emissions in monolayer phosphorene , 2015, Light: Science & Applications.

[25]  S. Louie,et al.  Electron-hole excitations and optical spectra from first principles , 2000 .

[26]  Xianfan Xu,et al.  Phosphorene: an unexplored 2D semiconductor with a high hole mobility. , 2014, ACS nano.

[27]  Akira Morita,et al.  Electronic Structure of Black Phosphorus in Tight Binding Approach , 1981 .

[28]  Aaron M. Jones,et al.  Highly anisotropic and robust excitons in monolayer black phosphorus. , 2014, Nature nanotechnology.

[29]  G. Steele,et al.  Isolation and characterization of few-layer black phosphorus , 2014, 1403.0499.

[30]  Yeonjin Yi,et al.  Observation of Tunable Band Gap and Anisotropic Dirac Semimetal State in Black Phosphorus. , 2015 .

[31]  Likai Li,et al.  Black phosphorus field-effect transistors. , 2014, Nature nanotechnology.

[32]  A S Rodin,et al.  Strain-induced gap modification in black phosphorus. , 2014, Physical review letters.

[33]  J. Shan,et al.  Atomically thin MoS₂: a new direct-gap semiconductor. , 2010, Physical review letters.

[34]  Xianfan Xu,et al.  Phosphorene: an unexplored 2D semiconductor with a high hole mobility. , 2014, ACS nano.

[35]  Extraordinarily Bound Quasi-One-Dimensional Trions in Two-Dimensional Phosphorene Atomic Semiconductors. , 2014, ACS nano.

[36]  Takashi Taniguchi,et al.  Direct-bandgap properties and evidence for ultraviolet lasing of hexagonal boron nitride single crystal , 2004, Nature materials.