Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Strain-induced large exciton energy shifts in buckled CdS nanowires.

ABSTRACT: Strain engineering can be utilized to tune the fundamental properties of semiconductor materials for applications in advanced electronic and photonic devices. Recently, the effects of large strain on the properties of nanostructures are being intensely investigated to further expand our insights into the physics and applications of such materials. In this Letter, we present results on controllable buckled cadmium-sulfide (CdS) optical nanowires (NWs), which show extremely large energy bandgap tuning by >250 meV with applied strains within the elastic deformation limit. Polarization and spatially resolved optical measurements reveal characteristics related to both compressive and tensile regimes, while microreflectance spectroscopy clearly demonstrates the effect of strain on the different types of excitons in CdS. Our results may enable strained NWs-based optoelectronic devices with tunable optical responses.

SUBMITTER: Sun L

PROVIDER: S-EPMC4236022 | biostudies-literature | 2013 Aug

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Strain-induced large exciton energy shifts in buckled CdS nanowires.

Sun Liaoxin L Kim Do Hyun DH Oh Kyu Hwan KH Agarwal Ritesh R

Nano letters 20130731 8

Strain engineering can be utilized to tune the fundamental properties of semiconductor materials for applications in advanced electronic and photonic devices. Recently, the effects of large strain on the properties of nanostructures are being intensely investigated to further expand our insights into the physics and applications of such materials. In this Letter, we present results on controllable buckled cadmium-sulfide (CdS) optical nanowires (NWs), which show extremely large energy bandgap tu ...[more]

PMID: 23899018

Similar Datasets

Emission energy, exciton dynamics and lasing properties of buckled CdS nanoribbons.

Project description:We report the modulation of emission energy, exciton dynamics and lasing properties in a single buckled CdS nanoribbon (NR) by strain-engineering. Inspired by ordered structure fabrication on elastomeric polymer, we develop a new method to fabricate uniform buckled NRs supported on polydimethylsiloxane (PDMS). Wavy structure, of which compressive and tensile strain periodically varied along the CdS NR, leads to a position-dependent emission energy shift as large as 14?nm in photoluminescence (PL) mapping. Both micro-PL and micro-reflectance reveal the spectral characteristics of broad emission of buckled NR, which can be understood by the discrepancy of strain-induced energy shift of A- and B-exciton of CdS. Furthermore, the dynamics of excitons under tensile strain are also investigated; we find that the B-exciton have much shorter lifetime than that of redshifted A-exciton. In addition, we also present the lasing of buckled CdS NRs, in which the strain-dominated mode selection in multi-mode laser and negligible mode shifts in single-mode laser are clearly observed. Our results show that the strained NRs may serve as new functional optical elements for flexible light emitter or on-chip all-optical devices.

| S-EPMC4876404 | biostudies-literature

Project description:In this report, comparative investigation of photoluminescence (PL) characteristics of CdS nanobelts (NBs) and nanowires (NWs) is presented. At low temperatures, emissions originate from radiative recombination of free exciton A, neutral donor bound exciton, neutral acceptor bound exciton and surface related exciton (SX) are observed and analyzed through power-dependent and temperature-dependent PL measurements. We found that SX emission takes a predominant role in emissions of CdS nanobelts and nanowires. There is a direct correlation between SX emission intensity and surface-to-volume ratio, which is the SX emission intensity is proportional to the superficial area of the nanostructures. At the same time, we found that the exciton-phonon interaction in the CdS NWs sample is weaker than that of CdS NBs sample. Furthermore, lasing action has been observed in CdS NBs sample at room temperature with lasing threshold of 608.13 mW/cm2. However, there is no lasing emission in CdS NWs sample. This phenomenon can be explained by the side effects (such as thermal effects) from surface deep level transitions caused the lower damage threshold in CdS NWs. Based on the observations and deductions presented here, SX emission significantly impact on the performance of nanostructures for lasing and light-emitting applications.

| S-EPMC6592998 | biostudies-literature

CdS-Nanowires Flexible Photo-detector with Ag-Nanowires Electrode Based on Non-transfer Process.

Project description:In this study, UV-visible flexible resistivity-type photo-detectors were demonstrated with CdS-nanowires (NWs) percolation network channel and Ag-NWs percolation network electrode. The devices were fabricated on Mixed Cellulose Esters (MCE) membrane using a lithographic filtration method combined with a facile non-transfer process. The photo-detectors demonstrated strong adhesion, fast response time, fast decay time, and high photo sensitivity. The high performance could be attributed to the high quality single crystalline CdS-NWs, encapsulation of NWs in MCE matrix and excellent interconnection of the NWs. Furthermore, the sensing performance was maintained even the device was bent at an angle of 90°. This research may pave the way for the facile fabrication of flexible photo-detectors with high performances.

| S-EPMC4761934 | biostudies-other

Strain induced exciton fine-structure splitting and shift in bent ZnO microwires.

Project description:Lattice strain is a useful and economic way to tune the device performance and is commonly present in nanostructures. Here, we investigated for the first time the exciton spectra evolution in bent ZnO microwires along the radial direction via high spatial/energy resolution cathodeluminescence spectroscopy at 5.5?K. Our experiments show that the exciton peak splits into multi fine peaks towards the compressive part while retains one peak in the tensile part and the emission peak displays a continuous blue-shift from tensile to compressive edges. In combination with first-principles calculations, we show that the observed NBE emission splitting is due to the valence band splitting and the absence of peak splitting in the tensile part maybe due to the highly localized holes in the A band and the carrier density distribution across the microwire. Our studies may pave the way to design nanophotonic and electronic devices using bent ZnO nanowires.

| S-EPMC3372877 | biostudies-other

?-NiS modified CdS nanowires for photocatalytic H2 evolution with exceptionally high efficiency.

Project description:Co-catalysis is regarded as a promising strategy to improve the hydrogen evolution performance of semiconductor-based photocatalysts. But developing a simple and effective technique to achieve the optimal synergy between co-catalysts and host photocatalysts has been a great challenge. Herein, hybrid photocatalysts consisting of ?-NiS modified CdS nanowires (NiS/CdS NWs) have been synthesized via a simple and green hydrothermal route using CdS NWs as the template from thiourea and nickel acetate in the presence of sodium hypophosphite. As a result, a metal Ni intermediate was formed via an electroless plating process assisted by H2PO2-, which facilitated the growth of highly conducting flake-like ?-NiS nanostructures onto the surface of the CdS NWs. With the optimal loading amount of NiS, the obtained NiS/CdS NWs present a record-high photocatalytic activity for H2 evolution in lactic acid aqueous solutions under visible light irradiation. At 25 °C, the rate of H2 evolution was measured as 793.6 ?mol h-1 (over a 5 mg photocatalyst sample), which is nearly 250-fold higher than that over pure CdS NWs, and the apparent quantum yield reached an exceptionally high value of 74.1% at 420 nm. The mechanism for the photocatalytic H2 evolution over the present NiS/CdS NWs was also proposed. This strategy would provide new insight into the design and development of high-performance heterostructured photocatalysts.

| S-EPMC5890328 | biostudies-literature

Interaction-induced zero-energy pinning and quantum dot formation in Majorana nanowires.

Project description:Majorana modes emerge in non-trivial topological phases at the edges of specific materials such as proximitized semiconducting nanowires under an external magnetic field. Ideally, they are non-local states that are charge-neutral superpositions of electrons and holes. However, in nanowires of realistic length their wave functions overlap and acquire a finite charge that makes them susceptible to interactions, specifically with the image charges that arise in the electrostatic environment. Considering a realistic three-dimensional model of the dielectric surroundings, here we show that, under certain circumstances, these interactions lead to a suppression of the Majorana oscillations predicted by simpler theoretical models, and to the formation of low-energy quantum-dot states that interact with the Majorana modes. Both features are observed in recent experiments on the detection of Majoranas and could thus help to properly characterize them.

| S-EPMC6122061 | biostudies-literature

Engineering the spin-flip limited exciton dephasing in colloidal CdSe/CdS quantum dots.

Project description:We have measured the intrinsic exciton dephasing in high-quality zinc blende CdSe/CdS colloidal quantum dots in the temperature range from 5 to 170 K using a sensitive three-beam photon echo technique in heterodyne detection, which is not affected by spectral diffusion. Pure dephasing via acoustic phonons dominates the initial dynamics, followed by an exponential zero-phonon line dephasing. From the temperature dependence of the zero-phonon line dephasing, the exciton lifetime, and the exciton thermalization within its fine structure, we show that the zero-phonon line dephasing of the lowest bright state originates from the phonon-assisted spin-flip to dark exciton states. Importantly, we can control the dephasing by tailoring the exciton fine structure through its dependence on the dot core size and shell thickness, as expected from the spin-flip mechanism. By reducing the electron-hole exchange interaction with increasing core size and delocalization of the electron wave function in the quasi-type-II core/shell band alignment, we find the longest zero-phonon line dephasing time of ?110 ps at 5 K in dots with the largest core diameter (5.7 nm) and the thickest CdSe shell (9 monolayers) in the series studied.

| S-EPMC3590878 | biostudies-other

Asymmetric photon transport in organic semiconductor nanowires through electrically controlled exciton diffusion.

Project description:The ability to steer the flow of light toward desired propagation directions is critically important for the realization of key functionalities in optical communication and information processing. Although various schemes have been proposed for this purpose, the lack of capability to incorporate an external electric field to effectively tune the light propagation has severely limited the on-chip integration of photonics and electronics. Because of the noninteractive nature of photons, it is only possible to electrically control the flow of light by modifying the refractive index of materials through the electro-optic effect. However, the weak optical effects need to be strongly amplified for practical applications in high-density photonic integrations. We show a new strategy that takes advantage of the strong exciton-photon coupling in active waveguides to effectively manipulate photon transport by controlling the interaction between excitons and the external electric field. Single-crystal organic semiconductor nanowires were used to generate highly stable Frenkel exciton polaritons with strong binding and diffusion abilities. By making use of directional exciton diffusion in an external electric field, we have realized an electrically driven asymmetric photon transport and thus directional light propagation in a single nanowire. With this new concept, we constructed a dual-output single wire-based device to build an electrically controlled single-pole double-throw optical switch with fast temporal response and high switching frequency. Our findings may lead to the innovation of concepts and device architectures for optical information processing.

| S-EPMC5856487 | biostudies-literature

Exciton binding energy of monolayer WS?.

Project description:The optical properties of monolayer transition metal dichalcogenides (TMDC) feature prominent excitonic natures. Here we report an experimental approach to measuring the exciton binding energy of monolayer WS? with linear differential transmission spectroscopy and two-photon photoluminescence excitation spectroscopy (TP-PLE). TP-PLE measurements show the exciton binding energy of 0.71 ± 0.01?eV around K valley in the Brillouin zone.

| S-EPMC4363839 | biostudies-other

Widely tunable GaAs bandgap via strain engineering in core/shell nanowires with large lattice mismatch.

Project description:The realisation of photonic devices for different energy ranges demands materials with different bandgaps, sometimes even within the same device. The optimal solution in terms of integration, device performance and device economics would be a simple material system with widely tunable bandgap and compatible with the mainstream silicon technology. Here, we show that gallium arsenide nanowires grown epitaxially on silicon substrates exhibit a sizeable reduction of their bandgap by up to 40% when overgrown with lattice-mismatched indium gallium arsenide or indium aluminium arsenide shells. Specifically, we demonstrate that the gallium arsenide core sustains unusually large tensile strain with hydrostatic character and its magnitude can be engineered via the composition and the thickness of the shell. The resulted bandgap reduction renders gallium arsenide nanowires suitable for photonic devices across the near-infrared range, including telecom photonics at 1.3 and potentially 1.55 μm, with the additional possibility of monolithic integration in silicon-CMOS chips.

| S-EPMC6595053 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data