•Isolated InAs QDs are realized on the sidewalls of core-shell GaAs/InP NWs by MOCVD.•Discrete sharp emission peaks are observed from the isolated InAs QDs.•Excitonic and biexcitonic emissions are observed from the QDs.We demonstrate the growth of isolated InAs quantum dots on the sidewalls of core-shell GaAs/InP nanowires based on the vapor-liquid-solid MOCVD method. The quantum dots are grown under the Stranski-Krastanov mode and exhibit defect-free zinc blende structure. Discrete sharp emission peaks are observed in the range of 1.37–1.39 eV, with linewidths ranging from several hundred μeV to 1 meV or more. Excitonic and biexcitonic emissions are observed, exhibiting different power-dependent intensity and linewidth behavior. This work may open a way for the fabrication of single photon devices based on the vapor-liquid-solid MOCVD method.

GaAs/InGaAs/GaAs nanowire core–multishell heterostructures with a strained radial In0.2Ga0.8As quantum well were fabricated by metal organic chemical vapor deposition. The quantum well exhibits a dislocation-free phase-pure zinc-blende structure. Low-temperature photoluminescence spectra of a single nanowire exhibit distinct resonant peaks in the range from 880 to 1000 nm, corresponding to the longitudinal modes of a Fabry–Pérot cavity. This suggests a decoupling of the gain medium and resonant cavity so that the quantum well provides the gain while the nanowire acts as the cavity. The resonant modes were observed at temperatures up to 240 K, exhibiting high power- and temperature-stability. The modes were blueshifted while decreasing the quantum well thickness due to enhanced quantum confinement. The results make the GaAs-based nanowire/quantum well hybrid structure promising for wavelength-tunable near-infrared nanolasers.

We investigate the formation and optical properties of InAs quantum dots on an InGaAs nanosubstrate. We find that Stranski–Krastanow InAs quantum dots are hardly formed on Au-catalyzed InGaAs nanowires due to the phase separation as well as stacking faults. High-quality Stranski–Krastanow InAs quantum dots are realized on a pure zinc blende InGaAs shell radially grown on a GaAs nanowire core. The quantum dots have a large size and regular shape, residing on a wetting layer of several nanometers. For optical characterization, we fabricate a “dot-in-well” structure by capping the quantum dots with InGaAs/GaAs double layers. Photoluminescence from the quantum dots is observed at 77 K, with a peak wavelength of 954 nm, which is distinctly redshifted compared with that of InAs quantum dots directly grown on GaAs nanowires. This work shows the potential of growing Stranski–Krastanow QDs on more types of NWs and obtaining longer wavelengths for wider applications.

•We propose a structure of plasmonic waveguiding.•This plasmonic waveguiding has a combination of high confinement and long propagation length.•There is a critical distance between silver nanowires that the influence of a silica substrate can be neglected when the distance is smaller than it.•The conclusion is applicable considering the roughness of the substrate surface.The plasmonic waveguiding properties of the gap plasmon mode between two adjacent silver nanowires with a substrate are theoretically investigated using finite element method. The results show that there is a critical gap distance between two silver nanowires which approximately equals to the radius of the nanowires. When the gap distance is less than the critical distance, the influence of the substrate on the gap plasmon mode can be neglected. The gap plasmon mode has a combination of high confinement and long propagation length. Moreover, the plasmonic waveguiding properties of the gap plasmon mode are not sensitive to the wire-to-substrate distance between silver nanowires and the substrate.

Formation mechanism and optical properties of InAs quantum dots (QDs) on the surface of GaAs nanowires (NWs) were investigated. This NW-QDs hybrid structure was fabricated by Au-catalyzed metal organic chemical vapor deposition. We found that the formation and distribution of QDs were strongly influenced by the deposition time of InAs as well as the diameter of GaAs NWs. A model based on the adatom diffusion mechanism was proposed to describe the evolution process of the QDs. Photoluminescence emission from the InAs QDs with a peak wavelength of 940 nm was observed at room temperature. The structure also exhibits a decoupling feature that QDs act as gain medium, while NW acts as Fabry–Perot cavity. This hybrid structure could serve as an important element in high-performance NW-based optoelectronic devices, such as near-infrared lasers, optical detectors, and solar cells.

In this paper, enhancement of bandwidth of supercontinuum generated in a normal dispersion-flattened microstructured fiber by using compressed pulse is demonstrated experimentally and numerically. Using high-order soliton compression effect, the standard single mode fiber is used as a pulse compressor. The experimental measured −10 dB spectral width is broadened from 75 nm to more than 140 nm by adding a 20 m long standard single mode fiber. Numerical analysis shows that using pulse compressed by a certain length fiber can increase the spectral bandwidth without making extra amplitude noise.Highlights► In this paper, we investigate the enhancement of supercontinuum bandwidth using compressed pulse experimentally and numerically. ► A certain length standard single mode fiber is used as a pulse compressor. ► The bandwidth of supercontinuum can be enhanced simply and effectively. ► The amplitude noise property of generated supercontinuum is not deteriorated.

InAs quantum dots (QDs) are grown epitaxially on Au-catalyst-grown GaAs nanowires (NWs) by metal organic chemical vapor deposition (MOCVD). These QDs are about 10–30 nm in diameter and several nanometers high, formed on the {112} side facets of the GaAs NWs. The QDs are very dense at the base of the NW and gradually sparser toward the top until disappearing at a distance of about 2 μm from the base. It can be concluded that these QDs are formed by adatom diffusion from the substrate as well as the sidewalls of the NWs. The critical diameter of the GaAs NW that is enough to form InAs QDs is between 120 and 160 nm according to incomplete statistics. We also find that these QDs exhibit zinc blende (ZB) structure that is consistent with that of the GaAs NW and their edges are faceted along particular surfaces. This hybrid structure may pave the way for the development of future nanowire-based optoelectronic devices.

We investigate the formation and optical properties of InAs quantum dots on an InGaAs nanosubstrate. We find that Stranski–Krastanow InAs quantum dots are hardly formed on Au-catalyzed InGaAs nanowires due to the phase separation as well as stacking faults. High-quality Stranski–Krastanow InAs quantum dots are realized on a pure zinc blende InGaAs shell radially grown on a GaAs nanowire core. The quantum dots have a large size and regular shape, residing on a wetting layer of several nanometers. For optical characterization, we fabricate a “dot-in-well” structure by capping the quantum dots with InGaAs/GaAs double layers. Photoluminescence from the quantum dots is observed at 77 K, with a peak wavelength of 954 nm, which is distinctly redshifted compared with that of InAs quantum dots directly grown on GaAs nanowires. This work shows the potential of growing Stranski–Krastanow QDs on more types of NWs and obtaining longer wavelengths for wider applications.