scholarly journals Room temperature nanocavity laser with interlayer excitons in 2D heterostructures

2019 ◽  
Vol 5 (4) ◽  
pp. eaav4506 ◽  
Author(s):  
Yuanda Liu ◽  
Hanlin Fang ◽  
Abdullah Rasmita ◽  
Yu Zhou ◽  
Juntao Li ◽  
...  
Keyword(s):  
Silicon Photonics ◽  
Room Temperature ◽  
Transition Metal Dichalcogenides ◽  
Infrared Range ◽  
Light Sources ◽  
Bandgap Engineering ◽  
Spectral Linewidth ◽  
Metal Dichalcogenides ◽  
Device Applications ◽  
Fundamental Research

Atomically thin layered two-dimensional (2D) materials have provided a rich library for both fundamental research and device applications. Bandgap engineering and controlled material response can be achieved from artificial heterostructures. Recently, excitonic lasers have been reported using transition metal dichalcogenides; however, the emission is still the intrinsic energy bandgap of the monolayers. Here, we report a room temperature interlayer exciton laser with MoS2/WSe2 heterostructures. The onset of lasing was identified by the distinct kink in the “L-L” curve and the noticeable spectral linewidth collapse. Different from visible emission of intralayer excitons in monolayer components, our laser works in the infrared range, which is fully compatible with the well-established technologies in silicon photonics. Long lifetime of interlayer excitons relaxes the requirement of the cavity quality factor by orders of magnitude. Room temperature interlayer exciton lasers might open new perspectives for developing coherent light sources with tailored optical properties on silicon photonics platforms.

scholarly journals The Deformation Behavior and Bending Emissions of ZnO Microwire Affected by Deformation-Induced Defects and Thermal Tunneling Effect

Sensors ◽  
2021 ◽  
Vol 21 (17) ◽  
pp. 5887
Author(s):  
Linlin Shi ◽  
Hong Wang ◽  
Xiaohui Ma ◽  
Yunpeng Wang ◽  
Fei Wang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Luminescent Properties ◽  
Tunneling Effect ◽  
Light Sources ◽  
Electrical Characteristics ◽  
Fundamental Research ◽  
Induced Defects ◽  
Theoretical Simulations ◽  
Bright Emission

The realization of electrically pumped emitters at micro and nanoscale, especially with flexibility or special shapes is still a goal for prospective fundamental research and application. Herein, zinc oxide (ZnO) microwires were produced to investigate the luminescent properties affected by stress. To exploit the initial stress, room temperature in situ elastic bending stress was applied on the microwires by squeezing between the two approaching electrodes. A novel unrecoverable deformation phenomenon was observed by applying a large enough voltage, resulting in the formation of additional defects at bent regions. The electrical characteristics of the microwire changed with the applied bending deformation due to the introduction of defects by stress. When the injection current exceeded certain values, bright emission was observed at bent regions, ZnO microwires showed illumination at the bent region priority to straight region. The bent emission can be attributed to the effect of thermal tunneling electroluminescence appeared primarily at bent regions. The physical mechanism of the observed thermoluminescence phenomena was analyzed using theoretical simulations. The realization of electrically induced deformation and the related bending emissions in single microwires shows the possibility to fabricate special-shaped light sources and offer a method to develop photoelectronic devices.

scholarly journals Optoelectronics with single layer group-VIB transition metal dichalcogenides

Nanophotonics ◽  
2018 ◽  
Vol 7 (10) ◽  
pp. 1589-1600 ◽  
Author(s):  
M.A. Khan ◽  
Michael N. Leuenberger
Keyword(s):  
Transition Metal ◽  
Electronic Devices ◽  
Transition Metal Dichalcogenides ◽  
Single Layer ◽  
Spin Orbit Coupling ◽  
Electroluminescent Devices ◽  
Metal Dichalcogenides ◽  
Fundamental Research ◽  
Excitonic Effects ◽  
Strong Spin

AbstractThe discovery of two-dimensional (2D) materials has opened up new frontiers and challenges for exploring fundamental research. Recently, single-layer (SL) transition metal dichalcogenides (TMDCs) have emerged as candidate materials for electronic and optoelectronic applications. In contrast to graphene, SL TMDCs have sizable band gaps that change from indirect to direct in SLs, which is useful in making thinner and more efficient electronic devices, such as transistors, photodetectors, and electroluminescent devices. In addition, SL TMDCs show strong spin-orbit coupling effects at the valence band edges, giving rise to the observation of valley-selective optical excitations. Here, we review the basic electronic and optical properties of pure and defected group-VIB SL TMDCs, with emphasis on the strong excitonic effects and their prospect for future optoelectronic devices.

scholarly journals Intrinsic lifetime of higher excitonic states in tungsten diselenide monolayers

Nanoscale ◽  
2019 ◽  
Vol 11 (25) ◽  
pp. 12381-12387 ◽  
Author(s):  
Samuel Brem ◽  
Jonas Zipfel ◽  
Malte Selig ◽  
Archana Raja ◽  
Lutz Waldecker ◽  
...  
Keyword(s):  
Transition Metal ◽  
Room Temperature ◽  
Transition Metal Dichalcogenides ◽  
Optical Spectra ◽  
Tungsten Diselenide ◽  
Dielectric Screening ◽  
Metal Dichalcogenides ◽  
Excitonic States

The reduced dielectric screening in atomically thin transition metal dichalcogenides allows to study the hydrogen-like series of higher exciton states in optical spectra even at room temperature.

scholarly journals Tungsten disulfide-based nanocomposites for photothermal therapy

2019 ◽  
Vol 10 ◽  
pp. 811-822 ◽  
Author(s):  
Tzuriel Levin ◽  
Hagit Sade ◽  
Rina Ben-Shabbat Binyamini ◽  
Maayan Pour ◽  
Iftach Nachman ◽  
...  
Keyword(s):  
Photothermal Therapy ◽  
Near Infrared ◽  
Transition Metal Dichalcogenides ◽  
Tungsten Disulfide ◽  
Ceric Ammonium Nitrate ◽  
Infrared Range ◽  
Metal Dichalcogenides ◽  
Current Article ◽  
Functionalized Nanotubes

Nanostructures of transition-metal dichalcogenides (TMDC) have raised scientific interest in the last few decades. Tungsten disulfide (WS2) nanotubes and nanoparticles are among the most extensively studied members in this group, and are used for, e.g., polymer reinforcement, lubrication and electronic devices. Their biocompatibility and low toxicity make them suitable for medical and biological applications. One potential application is photothermal therapy (PTT), a method for the targeted treatment of cancer, in which a light-responsive material is irradiated with a laser in the near-infrared range. In the current article we present WS2 nanotubes functionalized with previously reported ceric ammonium nitrate–maghemite (CAN-mag) nanoparticles, used for PTT. Functionalization of the nanotubes with CAN-mag nanoparticles resulted in a magnetic nanocomposite. When tested in vitro with two types of cancer cells, the functionalized nanotubes showed a better PTT activity compared to non-functionalized nanotubes, as well as reduced aggregation and the ability to add a second-step functionality. This ability is demonstrated here with two polymers grafted onto the nanocomposite surface, and other functionalities could be additional cancer therapy agents for achieving increased therapeutic activity.

scholarly journals Exciton–phonon coupling strength in single-layer MoSe2 at room temperature

2020 ◽  
Author(s):  
Donghai Li ◽  
Chiara Trovatello ◽  
Stefano Dal Conte ◽  
Matthias Nuß ◽  
Giancarlo Soavi ◽  
...  
Keyword(s):  
Room Temperature ◽  
Research Effort ◽  
Transition Metal Dichalcogenides ◽  
Optoelectronic Devices ◽  
Single Layer ◽  
Semiconductor Nanostructures ◽  
Phonon Coupling ◽  
Layer Transition ◽  
Fundamental Physics ◽  
Metal Dichalcogenides

Abstract Single-layer transition metal dichalcogenides (1L-TMDs) are at the center of an ever increasing research effort both in terms of fundamental physics and applications. Exciton–phonon coupling (EXPC) plays a key role in determining the photonic and (opto)electronic properties of 1L-TMDs. However, the EXPC strength has not been measured at room temperature. Here, we develop two-dimensional (2D) micro-spectroscopy to determine EXPC of 1L-MoSe2. We detect beating signals as a function of waiting time T, induced by the coupling between the A exciton and the A'1 optical phonon. Analysis of 2D beating maps provides the EXPC with the help of simulations. The Huang–Rhys factor of ~1 is larger than in most other inorganic semiconductor nanostructures. Our technique offers a unique tool to measure EXPC also in other 1L-TMDs and heterogeneous semiconducting systems with a spatial resolution ~260 nm, and will provide design-relevant parameters for the development of novel optoelectronic devices.

scholarly journals Enhancing monolayer photoluminescence on optical micro/nanofibers for low-threshold lasing

2019 ◽  
Vol 5 (11) ◽  
pp. eaax7398 ◽  
Author(s):  
Feng Liao ◽  
Jiaxin Yu ◽  
Zhaoqi Gu ◽  
Zongyin Yang ◽  
Tawfique Hasan ◽  
...  
Keyword(s):  
Room Temperature ◽  
Dynamic Range ◽  
Transition Metal Dichalcogenides ◽  
Pump Intensity ◽  
Environmental Stability ◽  
Quantum Yields ◽  
Light Emitters ◽  
Practical Applications ◽  
Metal Dichalcogenides ◽  
High Pump

Although monolayer transition metal dichalcogenides (TMDs) have direct bandgaps, the low room-temperature photoluminescence quantum yields (QYs), especially under high pump intensity, limit their practical applications. Here, we use a simple photoactivation method to enhance the room-temperature QYs of monolayer MoS2 grown on to silica micro/nanofibers by more than two orders of magnitude in a wide pump dynamic range. The high-density oxygen dangling bonds released from the tapered micro/nanofiber surface are the key to this strong enhancement of QYs. As the pump intensity increases from 10−1 to 104 W cm−2, our photoactivated monolayer MoS2 exhibits QYs from ~30 to 1% while maintaining high environmental stability, allowing direct lasing with greatly reduced thresholds down to 5 W cm−2. Our strategy can be extended to other TMDs and offers a solution to the most challenging problem toward the realization of efficient and stable light emitters at room temperature based on these atomically thin materials.

Large-area synthesis of transition metal dichalcogenides via CVD and solution-based approaches and their device applications

Nanoscale ◽  
2021 ◽  
Author(s):  
Anh Tuan Hoang ◽  
Kairui Qu ◽  
Xiang Chen ◽  
Jong-Hyun Ahn
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Transition Metal ◽  
Vapor Deposition ◽  
Transition Metal Dichalcogenides ◽  
Chemical Vapor ◽  
Large Area ◽  
Wafer Scale ◽  
Metal Dichalcogenides ◽  
Device Applications

This article reviews the latest advances in the synthesis of wafer-scale thin films using chemical vapor deposition and solution-based methods and various device applications.

Remarkably high thermal-driven MoS2 grain boundary migration mobility and its implications on defect healing

Nanoscale ◽  
2020 ◽  
Vol 12 (34) ◽  
pp. 17746-17753
Author(s):  
Xiangjun Liu ◽  
Zhi Gen Yu ◽  
Gang Zhang ◽  
Yong-Wei Zhang
Keyword(s):  
Robust Control ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Boundary Migration ◽  
Transition Metal Dichalcogenides ◽  
Grain Boundary Migration ◽  
Two Dimensional ◽  
Defect Healing ◽  
Metal Dichalcogenides ◽  
Device Applications

Two-dimensional (2D) transition-metal dichalcogenides (TMDs) hold great potential for many important device applications, such as field effect transistors and sensors, which require a robust control of defect type, density, and distribution.

scholarly journals Valley-Selective Response of Nanostructures Coupled to 2D Transition-Metal Dichalcogenides

2018 ◽  
Vol 8 (7) ◽  
pp. 1157 ◽  
Author(s):  
Alexander Krasnok ◽  
Andrea Alù
Keyword(s):  
Transition Metal ◽  
Room Temperature ◽  
State Of The Art ◽  
Transition Metal Dichalcogenides ◽  
Zone Boundary ◽  
Brillouin Zone Boundary ◽  
Directional Emission ◽  
Metal Dichalcogenides ◽  
On Chip ◽  
Valley Hall Effect

Monolayer (1L) transition-metal dichalcogenides (TMDCs) are attractive materials for several optoelectronic applications because of their strong excitonic resonances and valley-selective response. Valley excitons in 1L-TMDCs are formed at opposite points of the Brillouin zone boundary, giving rise to a valley degree of freedom that can be treated as a pseudospin, and may be used as a platform for information transport and processing. However, short valley depolarization times and relatively short exciton lifetimes at room temperature prevent using valley pseudospins in on-chip integrated valley devices. Recently, it was demonstrated how coupling these materials to optical nanoantennas and metasurfaces can overcome this obstacle. Here, we review the state-of-the-art advances in valley-selective directional emission and exciton sorting in 1L-TMDC mediated by nanostructures and nanoantennas. We briefly discuss the optical properties of 1L-TMDCs paying special attention to their photoluminescence/absorption spectra, dynamics of valley depolarization, and the valley Hall effect. Then, we review recent works on nanostructures for valley-selective directional emission from 1L-TMDCs.

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