Theoretical study on dynamic acoustic modulation of free carriers, excitons, and trions in 2D MoS2 flake

We present a self-consistent model calculation to study the influence of a radio-frequency surface acoustic wave (SAW) on the dynamic processes of photo-generated free carriers, excitons and trions in a 2D MoS2 flake with an odd number of layers. We found that the concentrations of excitons and trions decreased, while the lifetime of the free carriers increased when an external SAW field was applied. We attribute this phenomenon to the spatial separation of the electrons and holes, which are confined by a SAW-induced periodic type-II band-edge. We further studied the effect of the modulations on the spatiotemporal distributions of free carriers and excited quasiparticles by varying the amplitude and wavelength of the SAW field. We finally calculated the photoluminescent properties of the MoS2 flake under modulation of the SAW field and compared our results with those of recent experiments.

[1]  Z. Mi,et al.  Exciton kinetics, quantum efficiency, and efficiency droop of monolayer MoS₂ light-emitting devices. , 2014, Nano letters.

[2]  S. Shiokawa,et al.  Interactions of surface plasmons with surface acoustic waves and the study of the properties of Ag films , 1991 .

[3]  Aaron M. Jones,et al.  Electrically tunable excitonic light-emitting diodes based on monolayer WSe2 p-n junctions. , 2013, Nature nanotechnology.

[4]  Achim Wixforth,et al.  Scalable fabrication of a hybrid field-effect and acousto-electric device by direct growth of monolayer MoS2/LiNbO3 , 2015, Nature Communications.

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

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

[7]  A. Thilagam.  Exciton complexes in low dimensional transition metal dichalcogenides , 2014, 1407.0902.

[8]  Zhong Lin Wang,et al.  Piezoelectricity of single-atomic-layer MoS2 for energy conversion and piezotronics , 2014, Nature.

[9]  Andras Kis,et al.  Ultrasensitive photodetectors based on monolayer MoS2. , 2013, Nature nanotechnology.

[10]  B. Jonker,et al.  Charge Trapping and Exciton Dynamics in Large-Area CVD Grown MoS2 , 2016 .

[11]  M. H. Oliveira,et al.  Acousto-electric transport in epitaxial monolayer graphene on SiC , 2013 .

[12]  Achim Wixforth,et al.  Surface acoustic wave mediated coupling of free-space radiation into surface plasmon polaritons on plain metal films , 2010 .

[13]  F. Guinea,et al.  Coupling light into graphene plasmons through surface acoustic waves. , 2013, Physical review letters.

[14]  Leslie Y Yeo,et al.  Acoustically-Driven Trion and Exciton Modulation in Piezoelectric Two-Dimensional MoS2. , 2016, Nano letters.

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

[16]  G. Nash,et al.  Macroscopic acoustoelectric charge transport in graphene , 2013 .

[17]  S. Khanna,et al.  Damage coefficient associated with free exciton lifetime in GaAs irradiated with neutrons and electrons , 1992 .

[18]  P. Santos,et al.  Spatiotemporal carrier dynamics in quantum wells under surface acoustic waves , 2004 .

[19]  A. Ramasubramaniam.  Large excitonic effects in monolayers of molybdenum and tungsten dichalcogenides , 2012 .

[20]  Marten Richter,et al.  Trion formation dynamics in monolayer transition metal dichalcogenides , 2015, 1507.04463.

[21]  Hadis Morkoç,et al.  Charge transport by surface acoustic waves in GaAs , 1982 .

[22]  Jungwook Choi,et al.  Modulating Optoelectronic Properties of Two-Dimensional Transition Metal Dichalcogenide Semiconductors by Photoinduced Charge Transfer. , 2016, ACS nano.

[23]  A. Wixforth,et al.  Acoustically Driven Storage of Light in a Quantum Well , 1997 .

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

[25]  Wang Yao,et al.  Valley polarization in MoS2 monolayers by optical pumping. , 2012, Nature nanotechnology.

[26]  J. Kong,et al.  Trion-induced negative photoconductivity in monolayer MoS2. , 2014, Physical review letters.

[27]  G. Abstreiter,et al.  The Native Material Limit of Electron and Hole Mobilities in Semiconductor Nanowires. , 2016, ACS nano.

[28]  Weimann,et al.  Quantum oscillations in the surface-acoustic-wave attenuation caused by a two-dimensional electron system. , 1986, Physical review letters.

[29]  M. Jo,et al.  1s-intraexcitonic dynamics in monolayer MoS2 probed by ultrafast mid-infrared spectroscopy , 2016, Nature Communications.

[30]  Wood,et al.  Electric field dependence of optical absorption near the band gap of quantum-well structures. , 1985, Physical review. B, Condensed matter.

[31]  P‐Type Polar Transition of Chemically Doped Multilayer MoS2 Transistor , 2015, Advanced materials.

[32]  Bo Li,et al.  Optoelectronic memory using two-dimensional materials. , 2015, Nano letters.

[33]  C. Robert,et al.  Exciton radiative lifetime in transition metal dichalcogenide monolayers , 2016, 1603.00277.

[34]  Matthias Weiss,et al.  Dynamic acoustic control of individual optically active quantum dot-like emission centers in heterostructure nanowires. , 2014, Nano letters.

[35]  A. Chaplik,et al.  Two-dimensional plasmons (2DP) and acoustic waves in crystals , 1980 .

[36]  Achim Wixforth,et al.  Acoustically regulated carrier injection into a single optically active quantum dot , 2013, 1306.5954.

[37]  C. Somaschini,et al.  Acoustically driven photon antibunching in nanowires. , 2012, Nano letters.

[38]  Benjamin J. Carey,et al.  Plasmon resonances of highly doped two-dimensional MoS₂. , 2015, Nano letters.

[39]  J. Shan,et al.  Tightly bound trions in monolayer MoS2. , 2012, Nature materials.

[40]  P. Santos,et al.  Acoustoelectric transport at gigahertz frequencies in coated epitaxial graphene , 2016, 1903.05507.

[41]  Wang Yao,et al.  Valley-polarized exciton dynamics in a 2D semiconductor heterostructure , 2016, Science.

[42]  Achim Wixforth,et al.  Experimental investigation towards a periodically pumped single-photon source , 2006 .

[43]  Sandip Tiwari,et al.  Radiative lifetimes of excitons and trions in monolayers of the metal dichalcogenide MoS 2 , 2014, 1409.3996.

[44]  Qing Hua Wang,et al.  Electronics and optoelectronics of two-dimensional transition metal dichalcogenides. , 2012, Nature nanotechnology.