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Highly Transparent Contacts to the 1D Hole Gas in Ultrascaled Ge/Si Core/Shell Nanowires
摘要： Semiconductor-superconductor hybrid systems have outstanding potential for emerging high performance nanoelectronics and quantum devices. However, critical to their successful application is the fabrication of high quality and reproducible semiconductor-superconductor interfaces. Here, we realize and measure axial Al-Ge-Al nanowire heterostructures with atomically precise interfaces, enwrapped by an ultra-thin epitaxial Si layer further denoted as Al-Ge/Si-Al nanowire heterostructures. The heterostructures were synthesized by a thermally induced exchange reaction of single-crystalline Ge/Si core/shell nanowires and lithographically defined Al contact pads. Applying this heterostructure formation scheme enables self-aligned quasi one-dimensional crystalline Al leads contacting ultra-scaled Ge/Si segments with contact transparencies greater than 96%. Integration into back-gated field-effect devices and continuous scaling beyond lithographic limitations allows us to exploit the full potential of the highly transparent contacts to the 1D hole gas at the Ge-Si interface. This leads to the observation of ballistic transport as well as quantum confinement effects up to temperatures of 150 K. Low temperature measurements reveal proximity-induced superconductivity in the Ge/Si core/shell nanowires. The realization of a Josephson field-effect transistor allows us to study the sub-gap structure caused by multiple Andreev reflections. Most importantly, the absence of a quantum dot regime indicates a hard superconducting gap originating from the highly transparent contacts to the 1D hole-gas, which is potentially interesting for the study of Majorana zero modes. Moreover, underlining the importance of the proposed thermally induced Al-Ge/Si-Al heterostructure formation technique, our system could contribute to the development of key components of quantum computing such as gatemon or transmon qubits.
关键词： 1D hole gas,hard superconducting gap,transparent contacts,superconductor-semiconductor hybrids,nanowire heterostructure,germanium
更新于2025-09-12 10:27:22
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Data on lateral collection length of charge carriers depending on pre-white-light soaking process for metal mesh transparent electrode based Cu(In,Ga)Se2 solar cells
摘要： The authors have recently reported silver nanowire based Cu(In,Ga)Se2 solar cells [1,2]. Metal mesh based transparent electrodes other than the silver nanowire can be also employed or have a potential to provide a better performance for the solar cells. To select a suitable electrode for a solar cell among metal meshes, it is required to have data on the lateral collection length of charge carriers in the targeted cell. The method to determine the lateral collection has been reported in our previous publication [3]. Here, we report data on the effect of the light intensity during pre-white-light soaking on the lateral charge collection length for metal mesh transparent electrode based Cu(In,Ga)Se2 solar cells.
关键词： Transparent electrodes,Lateral collection length,CIGS,Metal mesh,Silver nanowire,Solar cells
更新于2025-09-12 10:27:22
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Flexible ITO-free sky-blue polymer light-emitting diodes and printed polymer solar cells based on AgNW/PI transparent conductive electrode
摘要： In this work, transparent and conductive as well as flexible silver nanowire/polyimide (AgNW/PI) composite film with an average figure of merit as high as 111.3, which is the ratio of electronic conductivity to optical conductivity, is produced by a simple peel-off method without any post treatments. When employing the AgNW/PI composite film as the flexible transparent conductive anode in blue polymer light-emitting diodes (PLEDs), the device shows a high external quantum efficiency of 3.42% which is comparable to the rigid ITO-based control device with an efficiency of 3.96%. Moreover, for the flexible printed polymer solar cell (PSCs) with AgNW/PI as the transparent conductive anode, a high power conversion efficiency of 4.01% is achieved, which is also comparable to that of the rigid ITO-based PSC. This work systematically demonstrates that AgNW/PI composite film has a promising prospect for application in all kinds of flexible optoelectronic devices, such as light-emitting diodes, solar cells, flat panel displays, and so on.
关键词： Printing,ITO-free,Flexible Ag nanowire/polyimide,Polymer solar cells,Polymer light-emitting diodes
更新于2025-09-12 10:27:22
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Design of Quantum Dot-Nanowire Single-Photon Sources that are Immune to Thermomechanical Decoherence
摘要： Nanowire antennas embedding a single quantum dot (QD) have recently emerged as versatile platforms to realize bright sources of quantum light. In this theoretical work, we show that the thermally driven, low-frequency vibrations of the nanowire have a major impact on the QD light emission spectrum. Even at liquid helium temperatures, these prevent the emission of indistinguishable photons. To overcome this intrinsic limitation, we propose three designs that restore photon indistinguishability thanks to a specific engineering of the mechanical properties of the nanowire. We anticipate that such a mechanical optimization will also play a key role in the development of other high-performance light-matter interfaces based on nanostructures.
关键词： single-photon sources,photon indistinguishability,quantum dot,nanowire,thermomechanical decoherence
更新于2025-09-12 10:27:22
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Tailoring the longitudinal electric fields of high-order laser beams and their direct verification in three dimensions
摘要： We demonstrate the tailoring of longitudinal electric fields that arise from tight focusing of spatially phase-shaped high-order laser beams, and verify their spatial distribution in three dimensions. To tailor the three-dimensional (3D) spatial distribution of longitudinal electric fields, we precisely control the relative phase delay between the two lobes of a HG10 laser beam using a spatial light modulator (SLM) before tight focusing. To verify the longitudinal electric fields in the focal volume, we employ 3D microscopic mapping of second-harmonic generation (SHG) from a single semiconductor nanowire that is extremely sensitive to the orientation of the longitudinal electric field. The technique is direct, general and expected to be useful in harnessing and in probing longitudinal electric fields with arbitrary spatial intensity distributions in the 3D focal volume.
关键词： Second-harmonic generation,Polarization,Longitudinal electric field,3D microscopy,Semiconductor nanowire
更新于2025-09-12 10:27:22
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High Efficiency Solar Cells from Extremely Low Minority Carrier Lifetime Substrates Using Radial Junction Nanowire Architecture
摘要： Currently, a significant amount of photovoltaic device cost is related to its requirement of high-quality absorber materials, especially in the case of III-V solar cells. Therefore, a technology that can transform a low cost, low minority carrier lifetime material into an efficient solar cell can be beneficial for future applications. Here, we transform an inefficient p-type InP substrate with a minority carrier lifetime less than 100 ps into an efficient solar cell by utilizing a radial p-n junction nanowire architecture. We fabricate a p-InP/n-ZnO/AZO radial heterojunction nanowire solar cell to achieve a photovoltaic conversion efficiency of 17.1%, the best reported value for radial junction nanowire solar cells. The quantum efficiency of ~ 95 % (between 550 – 750 nm) and short circuit current density of 31.3 mA/cm2 are amongst the best for InP solar cells. Besides, we also perform an advanced loss analysis of proposed solar cell to assess different loss mechanisms in the solar cell.
关键词： radial junction,III-V solar cell,selective contact,nanowire solar cell,heterojunction
更新于2025-09-12 10:27:22
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Correlated electro-optical and structural study of electrically tunable nanowire quantum dot emitters
摘要： Quantum dots inserted in semiconducting nanowires are an interesting platform for the fabrication of single photon devices. To fully understand the physical properties of these objects we need to correlate the optical, transport and structural properties on the same nanostructure. In this work, we study the spectral tunability of the emission of a single quantum dot in a GaN nanowire by applying external bias. The nanowires are dispersed and contacted on electron beam transparent Si3N4 membranes, so that transmission electron microscopy observations, photocurrent and micro-photoluminescence measurements under bias can be performed on the same specimen. The emission from a single dot blue or red shifts when the external electric field compensates or enhances the internal electric field generated by the spontaneous and piezoelectric polarization. A detailed study of two nanowire specimens emitting at 327.5 nm and 307.5 nm shows spectral shifts at rates of 20 and 12 meV/V, respectively. Theoretical calculations facilitated by the modelling of the exact heterostructure provide a good description of the experimental observations. When the bias-induced band bending is strong enough to favor tunneling of the electron in the dot towards the stem or the cap, the spectral shift saturates and additional transitions associated to charged excitons can be observed.
关键词： GaN,Quantum dot,quantum-confined Stark effect,microphotoluminescence,heterostructure,nanowire
更新于2025-09-12 10:27:22
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Non-contact Laser Printing of Ag Nanowire-based Electrode with Photodegradable Polymers
摘要： The roll-to-roll process is synonymous with newspaper production. If a similar high-throughput process is developed to fabricate electronics over large areas, it would revolutionize the printed electronics manufacturing process. Rapid fabrication of electrode, including patterning and nanoscale welding, is a necessary integration technique to reduce the duration of the process, but faces difficulties in being realized using conventional methods. This paper discusses material factors that affect printability, in the context of developing a promising fabrication technique called laser induced forward transfer (LIFT); LIFT is non-contact printing technique applied previously to realize simultaneous pattern deposition and nanowelding of Ag nanowire (AgNW)-based electrodes. A photodegradable polymer, which is a key component in the printing process to render droplet acceleration, is investigated with regards to its mechanical and optical properties. Furthermore, the printing process of the AgNW-based electrode is visualized, resulting in deeper understanding of LIFT. Knowledge of these factors will contribute to rapid and precise patterning of AgNW-based electrodes with high stretchability and transparency toward flexible optoelectronics devices.
关键词： Printable electronics,Metal nanowire,Transparent electrode
更新于2025-09-12 10:27:22
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Highly enhanced performance of integrated piezo photo-transistor with dual inverted OLED gate and nanowire array channel
摘要： Piezo-phototronic-e?ect possesses potential revolutionary applications in optoelectronic systems, malleable optical processing, biomedical diagnostics, and communication. Here, we report a novel structural device, dual piezo photo-transistor (DPPT), based on piezo invert-structured organic light emitting diode (OLED) as gate control and piezo nanowires (NWs) array as charge transport channel to realize tunable photoelectric properties dramatic enhancement achieved by piezo-phototronic-e?ect in both stimulation gate electrode and the metal-semiconductor-metal channel. Systematic analyses are carried out on electron generated as well as the electric ?eld distribution under various bending/strain direction and degree with the c-direction ZnO NWs grown both vertically and horizontally in OLED gate and NW channel, respectively. The piezo-phototronic transistors under mechanical deformation yield a current on/o? ratio of 106, more than 80 times higher as compared to the one without deformation. The enhancement of the integrated DPPTs, taking advantage of piezo-phototronic e?ect, may open up opportunities in innovative applications in various optoelectronic devices and ?exible integrated systems.
关键词： Piezo-phototronic-e?ect,Integrated device,Nanowire channel,Photo-transistor,Inverted OLED gate
更新于2025-09-12 10:27:22
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Nanoplasmonic 1D Diamond UV Photodetectors with High Performance
摘要： Diamond nanowires have recently drawn substantial attention due to their unique physical and chemical properties for electrochemical sensors, optoelectronics, and nanophotonics applications. However, diamond nanowire based ultraviolet photodetectors have not been reported because of the challenges involved in synthesizing crystalline diamond nanowires with controllable morphologies and, more fundamentally, the material’s high carrier concentration with low mobilities that limits the obtainable photoresponsivity. The synergetic integration of ultrananocrystalline diamond (UNCD) nanowires with nanoplasmonic enhancement by noble metal nanoparticles is a very promising approach to overcome these shortcomings. Here we report the fabrication of boron doped ultrananocrystalline diamond nanowires functionalized with the platinum nanoparticles to form self-powered ultraviolet photodetectors that exhibit an ultrahigh photoresponsivity of 388 Amp/Watt at 300 nm wavelength, a fast response time around 20 ms, and a good UV/visible rejection ratio of about five orders of magnitude under zero-bias condition.
关键词： ultraviolet photodetector,nanowire,metal nanoparticle,ultrananocrystalline diamond,nanoplasmonics
更新于2025-09-12 10:27:22