- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Coaxial GaAs/(In,Ga)As Dot-in-a-Well Nanowire Heterostructures for Electrically Driven Infrared Light Generation on Si in the Telecommunication O Band
摘要： Core-shell GaAs-based nanowires monolithically integrated on Si constitute a promising class of nanostructures that could enable light emitters for fast inter- and intrachip optical connections. We introduce and fabricate a coaxial GaAs/(In,Ga)As dot-in-a-well nanowire heterostructure to reach spontaneous emission in the Si transparent region, which is crucial for applications in Si photonics. Specifically, we achieve room temperature emission at 1.27 μm in the telecommunication O band. The presence of quantum dots in the heterostructure is evidenced by a structural analysis based on scanning transmission electron microscopy. The spontaneous emission of these nanowire structures is investigated by cathodoluminescence and photoluminescence spectroscopy. Thermal redistribution of charge carriers to larger quantum dots explains the long wavelength emission achieved at room temperature. Finally, in order to demonstrate the feasibility of the presented nanowire heterostructures as electrically driven light emitters monolithically integrated on Si, a light emitting diode is fabricated exhibiting room-temperature electroluminescence at 1.26 μm.
关键词： Electroluminescence,Si substrates,Dot-in-a-well,Light emitting diode,Nanowire heterostructures
更新于2025-09-12 10:27:22
-
High-specific-detectivity, low-dark-current Ge nanowire metal-semiconductor-metal photodetectors fabricated by Ge condensation method
摘要： We have investigated Ge nanowire (NW) metal-semiconductor-metal (MSM) photodetectors with high specific detectivity and low dark current, in which various sizes Ge NWs were fabricated by three-dimensional (3D) Ge condensation techniques. It has been demonstrated that the photocurrent gain increases significantly from 6.31×104 to 4.47×106 with the reduction of Ge NW width from 170 to 35 nm. A low dark current of 5.1 nA and an ultra-high specific detectivity of 1.26×1014 cm·Hz1/2·W-1 at 560 nm under 0.51 V bias are achieved for the 35 nm wide Ge NW photodetector. It has been proposed that the interface states provided by SiGeOx formed during Ge condensation process serve as electron traps to generate photogating effect, resulting in high photocurrent gain and high specific detectivity in the MSM photodetector. The fully complementary metal-oxide-semiconductor (CMOS) compatible and scalable process suggests a great potential of the Ge NW for low cost, high performance near infrared photodetectors.
关键词： gain,Ge nanowire photodetector,Ge condensation technique,photogating effect
更新于2025-09-12 10:27:22
-
Enhanced Efficiencies of Perovskite Solar Cells by Incorporating Silver Nanowires into the Hole Transport Layer
摘要： In this study, we incorporated silver nanowires (AgNWs) into poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) as a hole transport layer (HTL) for inverted perovskite solar cells (PVSCs). The e?ect of AgNW incorporation on the perovskite crystallization, charge transfer, and power conversion e?ciency (PCE) of PVSCs were analyzed and discussed. Compared with neat PEDOT:PSS HTL, incorporation of few AgNWs into PEDOT:PSS can signi?cantly enhance the PCE by 25%. However, the AgNW incorporation may result in performance overestimation due to the lateral charge transfer. The corrosion of AgNWs with a perovskite layer was discussed. Too much AgNW incorporation may lead to defects on the interface between the HTL and the perovskite layer. An extra PEDOT:PSS layer over the pristine PEDOT:PSS-AgNW layer can prevent AgNWs from corrosion by iodide ions.
关键词： PEDOT:PSS,inverted perovskite solar cell,hole transport layer,silver nanowire
更新于2025-09-11 14:15:04
-
Formation and characterization of charge coupled structure of polyoxometalate particles and a GaAs-based nanowire for readout of molecular charge states
摘要： To investigate the molecular charge dynamics of polyoxometalate (POM) molecules, we formed and characterized a charge coupled structure with POM molecular particles and a GaAs-based nanowire. In our system, the charge sensitivity was locally increased by capacitive coupling between a metal tip and the POM particle. Surface dispersion of POM particles on the GaAs nanowire was carried out in a controlled manner by choosing an appropriate solvent and POM concentration. We found that, after POM surface dispersion, the current in the GaAs nanowire remarkably increased by charging the POM particles using a conductive atomic force microscopy tip. The current change strongly depended on humidity of the measurement environment. The nanowire current under capacitive coupling between the conductive tip and the POM particle on the nanowire surface showed steps with a height of approximately 70 nA, suggesting that multiple hole charging and discharging occurred in the particle in a synchronized manner.
关键词： conductive atomic force microscopy,GaAs-based nanowire,molecular charge states,charge coupled structure,polyoxometalate
更新于2025-09-11 14:15:04
-
Halogen Vacancies Enable Ligand-Assisted Self-Assembly of Perovskite Quantum Dots into Nanowires
摘要： Interest has been growing in defects of halide perovskites in view of their intimate connection with key material optoelectronic properties. In perovskite quantum dots (PQDs), the influence of defects is even more apparent than in their bulk counterparts. By combining experiment and theory, we report herein a halide-vacancy-driven, ligand-directed self-assembly process of CsPbBr3 PQDs. With the assistance of oleic acid and didodecyldimethylammonium sulfide, surface-Br-vacancy-rich CsPbBr3 PQDs self-assemble into nanowires (NWs) that are 20–60 nm in width and several millimeters in length. The NWs exhibit a sharp photoluminescence profile ( (cid:2) 18 nm full-width at-half-maximum) that peaks at 525 nm. Our findings provide insight into the defect-correlated dynamics of PQDs and defect-assisted fabrication of perovskite materials and devices.
关键词： CsPbBr3,self-assembly,halide vacancy,nanowire,perovskite quantum dot
更新于2025-09-11 14:15:04
-
On‐Chip Integration of Single Photon Sources via Evanescent Coupling of Tapered Nanowires to SiN Waveguides
摘要： A method to integrate nanowire-based quantum dot single photon sources on-chip using evanescent coupling is demonstrated. By deterministically placing an appropriately tapered III-V nanowire, containing a single quantum dot, on top of a silicon-based ridge waveguide, the quantum dot emission directed toward the taper can be transferred to the ridge waveguide with calculated e?ciencies close to 100%. As the evanescent coupling is bidirectional, the source can be optically pumped in both free-space and through the ridge waveguide. The latter con?guration paves the way toward a self-contained, all-?ber, plug-and-play solution for applications requiring a bright on-demand single photon source. Using InAsP quantum dots embedded in InP nanowire waveguides, coupling e?ciencies to a SiN ridge waveguide of 74% with a single photon purity of 97% are demonstrated. The technique to demonstrate deterministic placement of single quantum emitters onto pre-fabricated waveguides is used, an important step toward the fabrication of complex quantum photonic circuits.
关键词： nanowire quantum dots,single photon sources,integrated quantum photonics
更新于2025-09-11 14:15:04
-
Suppressing Dark Counts of Multimode-Fiber-Coupled Superconducting Nanowire Single-Photon Detector
摘要： Large active-area superconducting nanowire single-photon detectors (SNSPDs) coupled with multimode fibers (MMFs) can provide high light-gathering capacity, which is essential for free-space detection applications in photon-starved regimes. However, MMF-coupled SNSPDs often suffer from large system dark count rates (DCRsys) over kHz due to blackbody radiation of the MMF at room temperature. Such large DCRsys would significantly degrade signal-to-noise ratio (SNR) of the receiving system. This paper reports an MMF-coupled large-active-area SNSPD system with low DCRsys by using a homemade cryogenic MMF filter bench. The filter bench, which consists of lenses and optical filters, can provide a high transmittance of about 80% at the central wavelength of the passband (1550 ± 12.5 nm) and a wide blocking range from 500 nm to over 6000 nm at 40 K. With using the filter bench, the DCRsys of an MMF-coupled 9-pixel SNSPD array with an active area of 50 μm in diameter is greatly suppressed by 23 dB with 1 dB loss of system detection efficiency (SDE). The detector demonstrates an SDE of 51% at a DCRsys of 100 Hz for 1550 nm photons. Thus, SNR of the detector is enhanced by about 160 times and the noise equivalent power is improved to 3×10?19 W/Hz1/2.
关键词： cryogenic MMF filter bench,multimode fibers (MMFs),Superconducting nanowire single-photon detectors (SNSPDs),dark count rates (DCRsys),signal-to-noise ratio (SNR)
更新于2025-09-11 14:15:04
-
Radiation Tolerant Nanowire Array Solar Cells
摘要： Space power systems require photovoltaics that are lightweight, efficient, reliable, and capable of operating for years or decades in space environment. Current solar panels use planar multijunction, III-V based solar cells with very high efficiency, but their specific power (power to weight ratio) is limited by the added mass of radiation shielding (e.g. coverglass) required to protect the cells from the high-energy particle radiation that occurs in space. Here we demonstrate that III-V nanowire-array solar cells have dramatically superior radiation performance relative to planar solar cell designs and show this for multiple cell geometries and materials, including GaAs and InP. Nanowire cells exhibit damage thresholds ranging from ~10-40 times higher than planar control solar cells when subjected to irradiation by 100-350 keV protons and 1 MeV electrons. Using Monte Carlo simulations, we show that this improvement is due in part to a reduction in the displacement density within the wires arising from their nanoscale dimensions. Radiation tolerance, combined with the efficient optical absorption and the improving performance of nanowire photovoltaics, indicates that nanowire arrays could provide a pathway to realize high-specific-power, substrate-free, III-V space solar cells with substantially reduced shielding requirements. More broadly, the exceptional reduction in radiation damage suggests that nanowire architectures may be useful in improving the radiation tolerance of other electronic and optoelectronic devices.
关键词： space environment,irradiation-induced defects,radiation hard,space solar cells,Monte Carlo simulations,nanowire solar cells,high specific power
更新于2025-09-11 14:15:04
-
Generation of a frequency-degenerate four-photon entangled state using a silicon nanowire
摘要： Integrated photonics is becoming an ideal platform for generating two-photon entangled states with high brightness, high stability, and scalability. This high brightness and high quality of photon pair sources encourages researchers further to study and manipulate multiphoton entangled states. Here, we experimentally demonstrate frequency-degenerate four-photon entangled state generation based on a single silicon nanowire 1 cm in length. The polarization encoded entangled states are generated with the help of a Sagnac loop using additional optical elements. The states are analyzed using quantum interference and state tomography techniques. As an example, we show that the generated quantum states can be used to achieve phase super-resolution. Our work provides a method for preparing indistinguishable multi-photon entangled states and realizing quantum algorithms in a compact on-chip setting.
关键词： silicon nanowire,frequency-degenerate,Integrated photonics,four-photon entangled state,quantum algorithms
更新于2025-09-11 14:15:04
-
A silicon-based quantum dot random laser
摘要： Herein, a quantum dot random laser was achieved using a silicon nanowire array. The silicon nanowire array was grown by a metal-assisted chemical etching method. A colloidal quantum dot solution was spin-coated on silicon nanowires to form the random laser. The performance of the random laser was controlled by the resistivity of silicon wafers and the length of silicon nanowires. A transition from incoherent random lasing to coherent random lasing was obtained by increasing the resistivity of the silicon wafers. The random lasing threshold increased with an increase in the length of the silicon nanowires. These results may be useful to explore high-performance silicon-based random lasers.
关键词： metal-assisted chemical etching,silicon nanowire array,coherent random lasing,quantum dot,random laser
更新于2025-09-11 14:15:04