Copper(i) sulfide: a two-dimensional semiconductor with superior oxidation resistance and high carrier mobility.

Two-dimensional (2D) semiconductors with suitable direct band gaps, high carrier mobility, and excellent open-air stability are especially desirable for material applications. Herein, we show theoretical evidence of a new phase of a copper(i) sulfide (Cu2S) monolayer, denoted δ-Cu2S, with both novel electronic properties and superior oxidation resistance. We find that both monolayer and bilayer δ-Cu2S have much lower formation energy than the known β-Cu2S phase. Given that β-Cu2S sheets have been recently synthesized in the laboratory (Adv. Mater.2016, 28, 8271), the higher stability of δ-Cu2S than that of β-Cu2S sheets suggests a high possibility of experimental realization of δ-Cu2S. Stability analysis indicates that δ-Cu2S is dynamically and thermally stable. Notably, δ-Cu2S exhibits superior oxidation resistance, due to the high activation energy of 1.98 eV for the chemisorption of O2 on δ-Cu2S. On its electronic properties, δ-Cu2S is a semiconductor with a modest direct band gap (1.26 eV) and an ultrahigh electron mobility of up to 6880 cm2 V-1 s-1, about 27 times that (246 cm2 V-1 s-1) of the β-Cu2S bilayer. The marked difference between the electron and hole mobilities of δ-Cu2S suggests easy separation of electrons and holes for solar energy conversion. Combination of these novel properties makes δ-Cu2S a promising 2D material for future applications in electronics and optoelectronics with high thermal and chemical stability.

[1]  Liang Ma,et al.  Tin and germanium based two-dimensional Ruddlesden-Popper hybrid perovskites for potential lead-free photovoltaic and photoelectronic applications. , 2018, Nanoscale.

[2]  Yang Hong,et al.  Monolayer and bilayer polyaniline C3N: two-dimensional semiconductors with high thermal conductivity. , 2018, Nanoscale.

[3]  J. Mun,et al.  Observation of photoluminescence from large-scale layer-controlled 2D ß-Cu2S synthesized by the vapor-phase sulfurization of copper thin films , 2017, Nanotechnology.

[4]  Jinlan Wang,et al.  Au6S2 monolayer sheets: metallic and semiconducting polymorphs , 2017 .

[5]  Jijun Zhao,et al.  Defects and oxidation of group-III monochalcogenide monolayers. , 2017, The Journal of chemical physics.

[6]  T. Heine,et al.  Single-Layer Tl2O: A Metal-Shrouded 2D Semiconductor with High Electronic Mobility. , 2017, Journal of the American Chemical Society.

[7]  Jijun Zhao,et al.  Oxidation Resistance of Monolayer Group-IV Monochalcogenides. , 2017, ACS applied materials & interfaces.

[8]  Lin-wang Wang,et al.  Large‐Size 2D β‐Cu2S Nanosheets with Giant Phase Transition Temperature Lowering (120 K) Synthesized by a Novel Method of Super‐Cooling Chemical‐Vapor‐Deposition , 2016, Advanced materials.

[9]  X. Duan,et al.  Van der Waals heterostructures and devices , 2016 .

[10]  Jijun Zhao,et al.  Atomic structures and electronic properties of phosphorene grain boundaries , 2016 .

[11]  A. Du,et al.  Graphene-like Two-Dimensional Ionic Boron with Double Dirac Cones at Ambient Condition. , 2016, Nano letters.

[12]  X. Zeng,et al.  Tuning the electronic properties of transition-metal trichalcogenides via tensile strain. , 2015, Nanoscale.

[13]  B. Fan,et al.  Synthesis of flower-like CuS hollow microspheres based on nanoflakes self-assembly and their microwave absorption properties , 2015 .

[14]  R. Wallace,et al.  Surface oxidation energetics and kinetics on MoS2 monolayer , 2015 .

[15]  S. Lebègue,et al.  Quasi-2D Cu2 S crystals on graphene: in-situ growth and ab-initio calculations. , 2015, Small.

[16]  Li Tao,et al.  Toward air-stable multilayer phosphorene thin-films and transistors , 2014, Scientific Reports.

[17]  Andres Castellanos-Gomez,et al.  Environmental instability of few-layer black phosphorus , 2014, 1410.2608.

[18]  D. Coker,et al.  Oxygen defects in phosphorene. , 2014, Physical review letters.

[19]  Yong-Wei Zhang,et al.  Layer-dependent Band Alignment and Work Function of Few-Layer Phosphorene , 2014, Scientific Reports.

[20]  Zhongfang Chen,et al.  Be(2)C monolayer with quasi-planar hexacoordinate carbons: a global minimum structure. , 2014, Angewandte Chemie.

[21]  Wen‐Cui Li,et al.  In Situ Electrochemical Generation of Mesostructured Cu2S/C Composite for Enhanced Lithium Storage: Mechanism and Material Properties , 2014 .

[22]  A. Burger,et al.  Probing excitonic states in suspended two-dimensional semiconductors by photocurrent spectroscopy , 2014, Scientific Reports.

[23]  Yanrong Li,et al.  Two-dimensional semiconductors with possible high room temperature mobility , 2014, Nano Research.

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

[25]  X. Kong,et al.  High-mobility transport anisotropy and linear dichroism in few-layer black phosphorus , 2014, Nature Communications.

[26]  D. Altamura,et al.  Metallic-like stoichiometric copper sulfide nanocrystals: phase- and shape-selective synthesis, near-infrared surface plasmon resonance properties, and their modeling. , 2013, ACS nano.

[27]  Giuseppe Iannaccone,et al.  Multiscale Modeling for Graphene-Based Nanoscale Transistors , 2013, Proceedings of the IEEE.

[28]  Jed I. Ziegler,et al.  Bandgap engineering of strained monolayer and bilayer MoS2. , 2013, Nano letters.

[29]  B. Wen,et al.  Enhanced wave absorption of nanocomposites based on the synthesized complex symmetrical CuS nanostructure and poly(vinylidene fluoride) , 2013 .

[30]  Hongzheng Chen,et al.  Graphene-like two-dimensional materials. , 2013, Chemical reviews.

[31]  Yanming Ma,et al.  An effective structure prediction method for layered materials based on 2D particle swarm optimization algorithm. , 2012, The Journal of chemical physics.

[32]  Xiaojun Wu,et al.  Two-dimensional boron monolayer sheets. , 2012, ACS nano.

[33]  H. Hng,et al.  Synthesis of CuxS/Cu Nanotubes and Their Lithium Storage Properties , 2012 .

[34]  J. Klimeš,et al.  Improved description of soft layered materials with van der Waals density functional theory , 2012, Journal of physics. Condensed matter : an Institute of Physics journal.

[35]  Lin-wang Wang.  High chalcocite Cu2S: a solid-liquid hybrid phase. , 2012, Physical review letters.

[36]  G. Fiori,et al.  Ab-Initio Simulations of Deformation Potentials and Electron Mobility in Chemically Modified Graphene and two-dimensional hexagonal Boron-Nitride , 2011, 1111.1953.

[37]  A. Tao,et al.  Localized surface plasmon resonances of anisotropic semiconductor nanocrystals. , 2011, Journal of the American Chemical Society.

[38]  Yanchao Wang,et al.  Predicting two-dimensional boron-carbon compounds by the global optimization method. , 2011, Journal of the American Chemical Society.

[39]  P. Jain,et al.  Size Dependence of a Temperature-Induced Solid-Solid Phase Transition in Copper(I) Sulfide , 2011 .

[40]  Lin-Wang Wang,et al.  Observation of Transient Structural-Transformation Dynamics in a Cu2S Nanorod , 2011, Science.

[41]  B. Sumpter,et al.  Density-functional approaches to noncovalent interactions: a comparison of dispersion corrections (DFT-D), exchange-hole dipole moment (XDM) theory, and specialized functionals. , 2011, The Journal of chemical physics.

[42]  A Paul Alivisatos,et al.  Localized surface plasmon resonances arising from free carriers in doped quantum dots. , 2011, Nature materials.

[43]  Y. Cho,et al.  Synthesis of Au−Cu2S Core−Shell Nanocrystals and Their Photocatalytic and Electrocatalytic Activity , 2010 .

[44]  Jian Lv,et al.  Crystal structure prediction via particle-swarm optimization , 2010, 1008.3601.

[45]  Jun‐Jie Zhu,et al.  Plasmonic Cu(2-x)S nanocrystals: optical and structural properties of copper-deficient copper(I) sulfides. , 2009, Journal of the American Chemical Society.

[46]  Se-Ho Lee,et al.  Highly scalable non-volatile and ultra-low-power phase-change nanowire memory. , 2007, Nature nanotechnology.

[47]  M. Lankhorst,et al.  Low-cost and nanoscale non-volatile memory concept for future silicon chips , 2005, Nature materials.

[48]  Andre K. Geim,et al.  Electric Field Effect in Atomically Thin Carbon Films , 2004, Science.

[49]  W. Jaegermann,et al.  Interface properties and band alignment of Cu2S/CdS thin film solar cells , 2003 .

[50]  G. Scuseria,et al.  Hybrid functionals based on a screened Coulomb potential , 2003 .

[51]  M. Careem,et al.  Preparation and characterization of CdS and Cu2S nanoparticle/polyaniline composite films , 2002 .

[52]  Mohd Zobir Hussein,et al.  Cathodic electrodeposition of Cu2S thin film for solar energy conversion , 2002 .

[53]  M. Ashry,et al.  Radiation effects on fabricated Cu2S/CdS heterojunction photovoltaic cells , 2001 .

[54]  Stefano de Gironcoli,et al.  Phonons and related crystal properties from density-functional perturbation theory , 2000, cond-mat/0012092.

[55]  R. Bader,et al.  Properties of Atoms in Molecules: Atoms Forming Molecules , 2000 .

[56]  G. Kresse,et al.  From ultrasoft pseudopotentials to the projector augmented-wave method , 1999 .

[57]  Andreas Savin,et al.  ELF: The Electron Localization Function , 1997 .

[58]  Burke,et al.  Generalized Gradient Approximation Made Simple. , 1996, Physical review letters.

[59]  Kresse,et al.  Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. , 1996, Physical review. B, Condensed matter.

[60]  H. Jónsson,et al.  Reversible work transition state theory: application to dissociative adsorption of hydrogen , 1994, chem-ph/9411012.

[61]  Blöchl,et al.  Projector augmented-wave method. , 1994, Physical review. B, Condensed matter.

[62]  S. Takagi,et al.  On the universality of inversion layer mobility in Si MOSFET's: Part I-effects of substrate impurity concentration , 1994 .

[63]  Andreas Savin,et al.  Electron Localization in Solid‐State Structures of the Elements: the Diamond Structure , 1992 .

[64]  Axel D. Becke,et al.  A Simple Measure of Electron Localization in Atomic and Molecular-Systems , 1990 .

[65]  R. Bader.  Atoms in molecules , 1990 .

[66]  H. Monkhorst,et al.  SPECIAL POINTS FOR BRILLOUIN-ZONE INTEGRATIONS , 1976 .