- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Photogating-controlled ZnO photodetector response for visible to near-infrared light
摘要： Over the last several decades, as a direct wide band gap semiconductor, zinc oxide (ZnO) nanomaterial has attracted lots of attention. However, the widely investigated ZnO materials are strongly limited in fast-response and broadband photodetectors due to their inherent weaknesses, so effective structure or mechanism of ZnO nanostructure photodetector is urgent. In this work, a photogating-controlled photodetector based on ZnO nanosheet-HfO2-lightly doped Si architecture was demonstrated. Its performance was improved significantly by the photogating-controlled local field at Si and HfO2 interfaces compared to other published work of ZnO. Consequently, the photodetector not only effectively balance the responsivity (as high as 5.6 A W-1) and response time (400 μs), but also broadens the response wavelength of the ZnO-based photodetectors from visible to near-infrared (~1200 nm). Additionally, the photogating-controlled ZnO photodetector enables high-resolution imaging both in visible and near-infrared bands. Our photogating-controlled ZnO photodetectors not only exemplify the control ability of the gate electrode in high mobility materials but also provide ideas for fast speed and high responsivity detection of high mobility materials.
关键词： ZnO nanosheet,photogating-controlled photodetectors,response wavelength,high-resolution imaging
更新于2025-09-23 15:21:01
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Holographic Materials and Optical Systems || Dynamic Imaging with X-ray Holography
摘要： X-ray holography is a type of coherent diffractive imaging where the phase information is physically encoded in the diffraction pattern by means of interference with a reference beam. The image of the diffracting specimen is obtained by a single Fourier transform of the interference pattern. X-ray holography is particularly well-suited for high resolution dynamic imaging because, intrinsically, the reconstructed image does not drift and the images show high contrast. Therefore, the motion of features between two images can be determined with a precision of better than 3 nm, as demonstrated recently. In this chapter, the technical aspects of X-ray holography are discussed from an end user perspective, focusing on what is required to obtain a high quality image in a short time. Specifically, the chapter discusses the key challenges of the technique, such as sample design and fabrication, beam requirements, suitable end stations, and how to implement pump-probe dynamic imaging. Good imaging parameters were found using simulations and experiments, and it is demonstrated how a deviation from the optimum value affects the image quality.
关键词： high resolution imaging,soft X-ray imaging,dynamic imaging,magnetic imaging,X-ray holography
更新于2025-09-12 10:27:22
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Monolithic integration of visible GaAs and near-infrared InGaAs for multicolor photodetectors by using high-throughput epitaxial lift-off toward high-resolution imaging systems
摘要： In this study, multicolor photodetectors (PDs) fabricated by using bulk p-i-n-based visible GaAs and near-infrared inGaAs structures were monolithically integrated through a high-throughput epitaxial lift-off (ELO) process. To perform multicolor detection in integrated structures, GaAs PDs were transferred onto inGaAs pDs by using a Y2o3 bonding layer to simultaneously detect visible and near-infrared photons and minimize the optical loss. As a result, it was found that the GaAs top PD and InGaAs bottom PD were vertically aligned without tilting in x-ray diffraction (XRD) measurement. A negligible change in the dark currents for each PD was observed in comparison with reference PDs through electrical characterization. Furthermore, through optical measurements and simulation, photoresponses were clearly revealed in the visible and near-infrared band for the material’s absorption region, respectively. Finally, we demonstrated the simultaneous multicolor detection of the visible and near-infrared region,which implies individual access to each PD without mutual interference. These results are a significant improvement for the fabrication of multicolor PDs that enables the formation of bulk-based multicolor PDs on a single substrate with a high pixel density and nearly perfect vertical alignment for high-resolution multicolor imaging.
关键词： high-resolution imaging,multicolor photodetectors,InGaAs,epitaxial lift-off,GaAs
更新于2025-09-12 10:27:22
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High-resolution speckle imaging
摘要： One of the most exciting and challenging pursuits of 21st-century astrophysics is to identify an exoplanet—that is, a planet orbiting an alien sun—on which life may exist. Such a planet is likely to reside in the habitable zone of its sun, meaning that it can harbor liquid water on its surface. Many astrobiologists posit that a life-harboring planet must also be small, rocky, and similar in density to our own. One critical input to any future discovery will be a precise determination of the planet radius, a value that will probably be obtained with the help of high-resolution speckle imaging.
关键词： speckle imaging,exoplanet,adaptive optics,atmospheric turbulence,high-resolution imaging
更新于2025-09-10 09:29:36
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K-domain transform based three-dimensional microscopy
摘要： A K-domain transform based three-dimensional microscopy technique is proposed. By illuminating an object with a light sheet along the optical axis and recording the complex amplitude, including the modulus and the phase (or wave-front) of the re?ected light in the epi-direction, the structure of the illuminated slice of the specimen can be clearly reconstructed by transforming the re?ected light from the vertical plane to the axial plane. While the principle of this proposed technique is theoretically illustrated, its feasibility is veri?ed both numerically and experimentally. Because the illuminating and collecting optics comprise a coaxial imaging system, the proposed technique can achieve high-speed and high-resolution three-dimensional imaging with a simple optical setup, which can be realized using a common commercial microscope with only slight modi?cation.
关键词： complex amplitude,three-dimensional microscopy,high-resolution imaging,K-domain transform,light sheet
更新于2025-09-10 09:29:36
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[IEEE 2018 International Symposium ELMAR - Zadar, Croatia (2018.9.16-2018.9.19)] 2018 International Symposium ELMAR - 3D Localization of Neurons in Bright-Field Histological Images
摘要： In this paper, we present a method for inferring the depth of neurons found in a bright-field microscopic image of a histological section of a human brain, digitized at high resolution in multiple planes along the z-axis. Individual neuron bodies are segmented and tracked throughout the depth of the whole image stack and placed at the appropriate z-level in the stack based on variations in image sharpness.
关键词： Digital Microscopy,Immunohistochemistry,High-resolution Imaging
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE 13th Annual International Conference on Nano/Micro Engineered and Molecular Systems (NEMS) - Singapore, Singapore (2018.4.22-2018.4.26)] 2018 IEEE 13th Annual International Conference on Nano/Micro Engineered and Molecular Systems (NEMS) - From Nanostructured Piezoelectric Materials to Broadband Transducers for High Resolution Ultrasonic Imaging
摘要： One-dimensional (1D) piezoelectric nanotubes have been fabricated and integrated for producing high frequency nanotube array ultrasonic transducers for high resolution ultrasonic imaging. We find that the nanotube structural feature and the unique nanoconfinement-induced crystal and polarization orientation lead to outstanding piezoelectric material properties and the resulting superior transducer performance. The nanotube array ultrasonic transducers show a broad bandwidth of 126 % (-6 dB) at 108 MHz, with significantly improved sensitivity in comparison with conventional thin film transducers despite the size shrinkage. We further demonstrate high resolution scanning ultrasonic imaging and photoacoustic imaging using the obtained nanotube array transducers, exhibiting great application values.
关键词： piezoelectric nanotubes,high resolution imaging,ultrasonic transducers,photoacoustic imaging
更新于2025-09-04 15:30:14
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[IEEE 2018 China International SAR Symposium (CISS) - Shanghai, China (2018.10.10-2018.10.12)] 2018 China International SAR Symposium (CISS) - Inverse Synthetic Aperture Ladar Demonstration and Outdoor Experiments
摘要： Inverse synthetic aperture ladar(ISAL)operates at light wavelength and utilizes the synthetic aperture technique, which can obtain very high resolution two-dimensional or three dimensional image of a moving target and thus have many important applications for target detection and recognition. With a very short wavelength, 10000 times smaller compared with that of microwave radar, ISAL can get a high angle resolution with a small telescope in microseconds. However, ISAL is more sensitive to many errors, such as ladar vibration, atmospheric turbulence, moving target jitter, etc., which bring many difficulties to implement an ISAL equipment. In this article, we present an ISAL demonstration and some outdoor experimental results. The ISAL transmits wideband coherent laser which is created by modulating a phase coded signal onto a continuous laser waveform at 1550nm, and detects weak echoes reflected from moving targets by a coherent detection system. A modified phased gradient autofocus algorithm(MPGA)is utilized to suppress errors and improve image quality. The ISAL demonstration acquires high-resolution images of 3-centimeter with a distance about 200m.
关键词： Inverse Synthetic Aperture Ladar,Phased Gradient Autofocus,High-resolution Imaging
更新于2025-09-04 15:30:14