MoS₂ nanosheet phototransistors with thickness-modulated optical energy gap.

We report on the fabrication of top-gate phototransistors based on a few-layered MoS(2) nanosheet with a transparent gate electrode. Our devices with triple MoS(2) layers exhibited excellent photodetection capabilities for red light, while those with single- and double-layers turned out to be quite useful for green light detection. The varied functionalities are attributed to energy gap modulation by the number of MoS(2) layers. The photoelectric probing on working transistors with the nanosheets demonstrates that single-layer MoS(2) has a significant energy bandgap of 1.8 eV, while those of double- and triple-layer MoS(2) reduce to 1.65 and 1.35 eV, respectively.

[1]  J. M. Baik,et al.  Band-gap transition induced by interlayer van der Waals interaction in MoS 2 , 2011 .

[2]  P. Kim,et al.  Energy band-gap engineering of graphene nanoribbons. , 2007, Physical review letters.

[3]  Hisato Yamaguchi,et al.  Photoluminescence from chemically exfoliated MoS2. , 2011, Nano letters.

[4]  A. Radenović,et al.  Single-layer MoS2 transistors. , 2011, Nature nanotechnology.

[5]  C. Berger,et al.  Ultrathin epitaxial graphite: 2D electron gas properties and a route toward graphene-based nanoelectronics. , 2004, cond-mat/0410240.

[6]  Arindam Ghosh,et al.  Nature of electronic states in atomically thin MoS₂ field-effect transistors. , 2011, ACS nano.

[7]  Thomas Heine,et al.  Influence of quantum confinement on the electronic structure of the transition metal sulfide T S 2 , 2011, 1104.3670.

[8]  J. Coleman,et al.  Two-Dimensional Nanosheets Produced by Liquid Exfoliation of Layered Materials , 2011, Science.

[9]  Andre K. Geim,et al.  Two-dimensional atomic crystals. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[10]  SUPARNA DUTTASINHA,et al.  Graphene: Status and Prospects , 2009, Science.

[11]  Rong Yang,et al.  Biocompatible inorganic fullerene-like molybdenum disulfide nanoparticles produced by pulsed laser ablation in water. , 2011, ACS nano.

[12]  Hua Zhang,et al.  Single-layer MoS2 phototransistors. , 2012, ACS nano.

[13]  Á. Rubio,et al.  Dielectric screening in two-dimensional insulators: Implications for excitonic and impurity states in graphane , 2011, 1104.3346.

[14]  Andras Kis,et al.  Stretching and breaking of ultrathin MoS2. , 2011, ACS nano.

[15]  G. Fudenberg,et al.  Ultrahigh electron mobility in suspended graphene , 2008, 0802.2389.

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

[17]  F. Guinea,et al.  Coulomb blockade in graphene nanoribbons. , 2007, Physical review letters.

[18]  A. Splendiani,et al.  Emerging photoluminescence in monolayer MoS2. , 2010, Nano letters.

[19]  L. Wirtz,et al.  Phonons in single-layer and few-layer MoS2 , 2011 .

[20]  D. Jena,et al.  Enhancement of carrier mobility in semiconductor nanostructures by dielectric engineering. , 2007, Physical review letters.

[21]  Kimoon Lee,et al.  Interfacial Trap Density‐of‐States in Pentacene‐ and ZnO‐Based Thin‐Film Transistors Measured via Novel Photo‐excited Charge‐Collection Spectroscopy , 2010, Advanced materials.

[22]  S. Lebègue,et al.  Electronic structure of two-dimensional crystals from ab-initio theory , 2009, 0901.0440.

[23]  Branimir Radisavljevic,et al.  Integrated circuits and logic operations based on single-layer MoS2. , 2011, ACS nano.

[24]  Hugen Yan,et al.  Anomalous lattice vibrations of single- and few-layer MoS2. , 2010, ACS nano.

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

[26]  B. Radisavljevic,et al.  Visibility of dichalcogenide nanolayers , 2010, Nanotechnology.