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oe1(光电查) - 科学论文

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出版时间
  • 2018
研究主题
  • differential low noise amplifier
  • GaAs pHEMT
  • Square Kilometre Array (SKA)
  • fully- integrated
  • balun
  • broadband
  • S-band
应用领域
  • Electronic Science and Technology
机构单位
  • National Taiwan University
  • Academia Sinica
156 条数据
?? 中文（中国） ▾

  • Single GaAs nanowire based photodetector fabricated by dielectrophoresis

    摘要： Mechanical manipulation of nanowires (NWs) for their integration in electronics is still problematic because of their reduced dimensions, risking to produce mechanical damage to the NW structure and electronic properties during the assembly process. In this regard, contactless NW manipulation based methods using non-uniform electric fields, like dielectrophoresis (DEP) are usually much softer than mechanical methods, offering a less destructive alternative for integrating nanostructures in electronic devices. Here, we report a feasible and reproducible dielectrophoretic method to assemble single GaAs NWs (with radius 35–50 nm, and lengths 3–5 μm) on conductive electrodes layout with assembly yields above 90% per site, and alignment yields of 95%. The electrical characteristics of the dielectrophoretic contact formed between a GaAs NW and conductive electrodes have been measured, observing Schottky barrier like contacts. Our results also show the fast fabrication of diodes with rectifying characteristics due to the formation of a low-resistance contact between the Ga catalytic droplet at the tip of the NW when using Al doped ZnO as electrode. The current-voltage characteristics of a single Ga-terminated GaAs NW measured in dark and under illumination exhibit a strong sensitivity to visible light under forward bias conditions (around two orders of magnitude), mainly produced by a change on the series resistance of the device.

    关键词： chemical beam epitaxy,optoelectronics,dielectrophoresis,nanowire assembly,GaAs nanowire photodetector,nanofabrication

    更新于2025-09-23 15:19:57

  • Enhancement of the optical gain in GaAs nanocylinders for nanophotonic applications

    摘要： Semiconductor nanolasers based on microdisks, photonic crystal cavities, and metallo-dielectric nanocavities have been studied during the last few decades for on-chip light source applications. However, practical realization of low threshold, room temperature semiconductor nanolasers is still a challenge due to the large surface-to-volume ratio of the nanostructures, which results in low optical gain and hence higher lasing threshold. Furthermore, the gain in nanostructures is an important parameter for designing all-dielectric metamaterial-based active applications. Here, we investigate the impact of p-type doping, compressive strain, and surface recombination on the gain spectrum and the spatial distribution of carriers in GaAs nanocylinders. Our analysis reveals that the lasing threshold can be lowered by choosing the right doping concentration in the active III–V material combined with compressive strain. This combination of strain and p-type doping shows 100× improvement in gain and approximately five times increase in modulation bandwidth for high-speed operation.

    关键词： surface recombination,optical gain,compressive strain,GaAs nanocylinders,nanophotonic applications,p-type doping

    更新于2025-09-23 15:19:57

  • Broadband, wide-angle antireflection in GaAs through surface nano-structuring for solar cell applications

    摘要： We demonstrate broadband and wide-angle antireflective surface nanostructuring in GaAs semiconductors using variable dose electron-beam lithography (EBL). Various designed structures are written with EBL on a positive EB-resist coated GaAs and developed followed by shallow inductively coupled plasma etching. An optimized nanostructured surface shows a reduced surface reflectivity down to less than 2.5% in the visible range of 450–700 nm and an average reflectance of less than 4% over a broad near-infrared wavelength range from 900–1400 nm. The results are obtained over a wide incidence angle of 33.3°. This study shows the potential for anti-reflective structures using a simpler reverse EBL process which can provide optical absorption or extraction efficiency enhancement in semiconductors relevant to improved performance in solar photovoltaics or light-emitting diodes.

    关键词： GaAs,surface nano-structuring,broadband,solar cell applications,wide-angle,antireflection

    更新于2025-09-23 15:19:57

  • Multiple epitaxial lift-off of stacked GaAs solar cells for low-cost photovoltaic applications

    摘要： This paper presents a multilayer peeling from a stacked cell structure as an approach for the cost reduction of III–V solar cells. We demonstrate the separation of two-layer stacked GaAs solar cells with Al(Ga)As release layers on the GaAs substrate into individual layers without cracks. The cells in each layer peeled from the stacked structure show equivalent device performances. Thermal cycling tests with repeated heating to 85 °C and cooling to ?40 °C show that the flexible GaAs thin-film cell exhibits a high durability against temperature changes. Further, a damp heat test conducted at 85 °C and 85% humidity indicates that the cell has long-term stability. These results suggest that the flexible GaAs thin-film cells fabricated by peeling from stacked structures have a high reliability and prove that the separation of the stacked cell structures into individual layers is effective in fabricating low-cost III–V solar cells.

    关键词： epitaxial lift-off,cost reduction,damp heat test,photovoltaic applications,thermal cycling,GaAs solar cells

    更新于2025-09-23 15:19:57

  • Embedding physics domain knowledge into a Bayesian network enables layer-by-layer process innovation for photovoltaics

    摘要： Process optimization of photovoltaic devices is a time-intensive, trial-and-error endeavor, which lacks full transparency of the underlying physics and relies on user-imposed constraints that may or may not lead to a global optimum. Herein, we demonstrate that embedding physics domain knowledge into a Bayesian network enables an optimization approach for gallium arsenide (GaAs) solar cells that identifies the root cause(s) of underperformance with layer-by-layer resolution and reveals alternative optimal process windows beyond traditional black-box optimization. Our Bayesian network approach links a key GaAs process variable (growth temperature) to material descriptors (bulk and interface properties, e.g., bulk lifetime, doping, and surface recombination) and device performance parameters (e.g., cell efficiency). For this purpose, we combine a Bayesian inference framework with a neural network surrogate device-physics model that is 100× faster than numerical solvers. With the trained surrogate model and only a small number of experimental samples, our approach reduces significantly the time-consuming intervention and characterization required by the experimentalist. As a demonstration of our method, in only five metal organic chemical vapor depositions, we identify a superior growth temperature profile for the window, bulk, and back surface field layer of a GaAs solar cell, without any secondary measurements, and demonstrate a 6.5% relative AM1.5G efficiency improvement above traditional grid search methods.

    关键词： Bayesian network,GaAs solar cells,photovoltaics,neural network surrogate model,process optimization

    更新于2025-09-23 15:19:57

  • A study on triple-junction GaInP2/InGaAs/Ge space grade solar cells irradiated by 24.5??MeV high-energy protons

    摘要： This paper was reported high-energy proton exposure effects on triple-junction GaInP2/InGaAs/Ge space grade solar cells. In order to explore the degradation of solar cells in hard radiation environments detailed and systematic analysis were performed, and the results were presented. The irradiation process was carried out using 24.5 MeV protons with doses ranging from 0 to 170 Gy. The degradation of output parameters of solar cells was studied as a function of damaged dose using light current–voltage measurements. The current–voltage characteristics indicated that the short circuit current was degraded less than the open circuit voltage because the base sub-cell of GaAs was significantly damaged. To analyze the effects of radiation-induced displacement damage on cell performance SRIM simulation was performed. Capacitance and conductance measurements were done to knowledge about the carrier concentration and interface trap density. A decrease in carrier concentration and a small increase in interface trap density were observed.

    关键词： Conductance method,Triple-junction,GaInP2/GaAs solar cells,Proton irradiation

    更新于2025-09-23 15:19:57

  • High-Efficiency Multiple Quantum Well Triple-Junction Tandem Solar Cell

    摘要： This work shows the design of a high-efficiency solar cell in an indium-gallium-arsenide/–gallium-arsenide multiple quantum well (MQW) structure. The main concerns regarding the solar cell are its fabrication complexity, design complexity, and efficiency. Tandem solar cells are designed to absorb the maximum amount of solar energy. In a tandem structure, different positive-negative junctions are responsible for absorbing different portions of the solar spectrum. Besides this, the embedded MQW structure also helps to increase the efficiency of the solar cell. The maximum efficiency of the tandem solar cell in the different material structures is reported to be around 45%–46%. Proper matching of different material parameters such as the lattice-matched semiconductor and thickness of the tandem solar cell can increase the efficiency of the solar cell. This paper introduces a tandem solar cell having an efficiency of around 50%. This comparative study shows the improved performance of the proposed solar cell. A graphical user interface is also developed for solar cell simulation.

    关键词： tandem solar cell,multi-quantum well,InGaAs-GaAs,quantum well,Solar cell

    更新于2025-09-23 15:19:57

  • All-photonic quantum teleportation using on-demand solid-state quantum emitters

    摘要： All-optical quantum teleportation lies at the heart of quantum communication science and technology. This quantum phenomenon is built up around the nonlocal properties of entangled states of light that, in the perspective of real-life applications, should be encoded on photon pairs generated on demand. Despite recent advances, however, the exploitation of deterministic quantum light sources in push-button quantum teleportation schemes remains a major open challenge. Here, we perform an important step toward this goal and show that photon pairs generated on demand by a GaAs quantum dot can be used to implement a teleportation protocol whose fidelity violates the classical limit (by more than 5 SDs) for arbitrary input states. Moreover, we develop a theoretical framework that matches the experimental observations and that defines the degree of entanglement and indistinguishability needed to overcome the classical limit independently of the input state. Our results emphasize that on-demand solid-state quantum emitters are one of the most promising candidates to realize deterministic quantum teleportation in practical quantum networks.

    关键词： GaAs quantum dot,entangled photon pairs,quantum emitters,quantum teleportation,quantum communication

    更新于2025-09-23 15:19:57

  • A broadband GaAs pHEMT low noise driving amplifier with current reuse and self-biasing technique

    摘要： A K/Ka-band two-stage low noise driving ampli?er using a 0.15 lm GaAs pHEMT for low noise technology is designed and fabricated. In order to achieve broadband driving capability with low power consumption, current reuse technique is adopted to feed both transistors with the same DC power supply, which theoretically cuts the total current consumption in half. In addition, self-biasing technique is utilized to minimize both external power supply pads and chip footprint, which reduces the number of supply pads to a minimum of two (1 power pad and 1 ground pad). The circuit topology analysis and design procedures are also presented with an emphasis on noise ?gure and P1dB optimization. The low noise driving ampli?er demonstrates a - 3 dB bandwidth of wider than 11 GHz, a power gain of 17 dB, an in-band mean noise ?gure of 2.2 dB and an in-band mean output P1dB of 6 dBm. The DC power consumption is 9.1 mA@3.3 V power supply. The chip size is 1 mm 9 1.5 mm with only 1 external DC feed pad (3.3 V) and 1 ground pad (0 V). With the performance comparable to typical two-stage dual-bias low noise driving ampli?er counterparts, the proposed MMIC is more attractive to chip/system users in volume-limited and power-contrained applications.

    关键词： Ka-band,Pseudomorphic high electron mobility transistor (pHEMT),GaAs,Low noise driving ampli?er,Monolithic microwave integrated circuit (MMIC)

    更新于2025-09-19 17:15:36

  • [IEEE 2018 14th IEEE International Conference on Solid-State and Integrated Circuit Technology (ICSICT) - Qingdao (2018.10.31-2018.11.3)] 2018 14th IEEE International Conference on Solid-State and Integrated Circuit Technology (ICSICT) - A 1.2-dB Noise Figure Broadband GaAs Low-Noise Amplifier with 17-dB Gain for Millimeter-Wave 5G Base-Station

    摘要： A 24-30GHz low-noise amplifier (LNA) with 1.2-dB noise figure (NF) is designed for millimeter-wave 5G stations. The LNA has 2 stages, 1st stage utilizes source degeneration inductor for simultaneous noise and input match. 2nd stage uses the same structure for staging match and the trade-off between gain and noise optimization. A structure of parallel resistor and capacitor is utilized for bandwidth and stability. Simulation result shows that the LNA achieves peak gain of 17.8-dB, and the 1-dB bandwidth is over 6-GHz. NF is below 1.35-dB in the bandwidth.

    关键词： low-noise amplifier,pHEMT,millimeter-wave,5G,GaAs,noise figure

    更新于2025-09-19 17:15:36