排序方式: 共有12条查询结果,搜索用时 31 毫秒
1.
E. P. G. Smith E. A. Patten P. M. Goetz G. M. Venzor J. A. Roth B. Z. Nosho J. D. Benson A. J. Stoltz J. B. Varesi J. E. Jensen S. M. Johnson W. A. Radford 《Journal of Electronic Materials》2006,35(6):1145-1152
High-performance 20-μm unit-cell two-color detectors using an n-p+-n HgCdTe triple-layer heterojunction (TLHJ) device architecture grown by molecular beam epitaxy (MBE) on (211)-oriented CdZnTe
substrates with midwavelength (MW) infrared and long wavelength (LW) infrared spectral bands have been demonstrated. Detectors
with nominal MW and LW cut-off wavelengths of 5.5 μm and 10.5 μm, respectively, exhibit 78 K LW performance with >70 % quantum
efficiency, reverse bias dark currents below 300 pA, and RA products (zero field of view, 150-mV bias) in excess of 1×103 Ωcm2. Temperature-dependent current-voltage (I–V) detector measurements show diffusion-limited LW dark current performance extending
to temperatures below 70 K with good operating bias stability (150 mV ± 50 mV). These results reflect the successful implementation
of MBE-grown TLHJ detector designs and the introduction of advanced photolithography techniques with inductively coupled plasma
(ICP) etching to achieve high aspect ratio mesa delineation of individual detector elements with benefits to detector performance.
These detector improvements complement the development of high operability large format 640×480 and 1280×720 two-color HgCdTe
infrared focal plane arrays (FPAs) to support third generation forward looking infrared (FLIR) systems. 相似文献
2.
3.
Ichiro Shimizu Takeji Abe Takayoshi Nosho Masahiro Wakayama 《Metals and Materials International》1998,4(4):939-943
Roughening behavior of the free surface of polycrystalline iron during plane strain compression is investigated experimentally.
The changes in the shape of the free surface, which is roughened during plastic deformation, are observed in the three-dimensions.
It is found that the mountains and the valleys of the roughened shape tend to elongate in the constrained direction for the
specimen with isotropic grain shape. The shapes of the roughness curves in the loading direction and in the constrained direction
are compared. The normalized height distribution of the roughness curve in the constrained direction is symmetric, while that
of the roughness curve in the loading direction is asymmetric and positively skew during plane strain compression. Based on
a simple simulation of the roughness curves by a random midpoint displacement method, this difference is supposed to be caused
by the constraint of the material flow under plane strain condition. 相似文献
4.
Ryoichi Koterazawa Takayoshi Nosho 《Fatigue & Fracture of Engineering Materials & Structures》1992,15(1):103-113
Fatigue crack growth behaviour under intermittent overstressing was investigated in moist air, dry air, nitrogen and vacuum with low carbon steels under tension-compression loading with a few tests under compression-tension loading. A very small number of cycles of overstress applied intermittently during a very large number of cycles of understress below threshold caused significant acceleration, of about one hundred times, in crack growth rate as compared to the case of steady cyclic stress in the cases of moist air, dry air and nitrogen. In the region of low understress, the acceleration in moist air was appreciably less than that in dry air and nitrogen due to oxide-induced crack closure. The acceleration in vacuum was smaller than that in other environments over all understress levels, possibly because of rewelding. There was no effect of an overstress sequence on the acceleration. 相似文献
5.
Kazuhiro Akiyama Nosho Toyama Kazuyoshi Muraoka Makoto Tsunashima 《Journal of the American Ceramic Society》1998,81(4):1071-1073
The physical and chemical configuration of anatase-form titanium dioxide pigment particles was investigated with a field-emission gun using transmission electron microscopy and energy-dispersive spectroscopy (EDX). The particle was ∼0.2 µm in average size and had an amorphous-surface-layer thickness of 1-2 nm around the single-crystallized matrix. Niobium that had segregated in the amorphous surface layer was detected via EDX analysis. 相似文献
6.
We have constructed an optical microscopy system to automatically locate, count, and determine the size of polycrystalline
“void” defects on epitaxial layers of HgCdTe grown on CdZnTe or Si substrates. Void macrodefects are readily imaged because
their polycrystalline surface is rough, and consequently they scatter light out of the image under specular reflection imaging
conditions. Using a computer-controlled stage to move the wafer, a succession of individual, contiguous bright-field images
is recorded over the entire wafer. Each image is analyzed by software to locate and characterize all the light-scattering
objects present in the frame. Several different representations of the spatial distribution and size of defects are generated,
and these can be presented either as false-color density maps or dot-location maps. In addition, various types of statistics
on the defect population and size distributions are also available. These data not only convey overall information on the
quality of a given wafer, and as such are quite useful for screening to determine which wafers are suitable for array fabrication,
but they also allow inferences to be made concerning the origin or root cause of different classes of defects. Several examples
are presented to illustrate the use of full-wafer defect mapping to identify macrodefect problems in HgCdTe growth on CdZnTe
that can arise from substrate temperature lateral nonuniformity, nonmatched source flux angular distributions, substrate contamination,
and intrinsic substrate imperfections. 相似文献
7.
HgCdTe focal plane arrays for dual-color mid- and long-wavelength infrared detection 总被引:1,自引:0,他引:1
E. P. G. Smith L. T. Pham G. M. Venzor E. M. Norton M. D. Newton P. M. Goetz V. K. Randall A. M. Gallagher G. K. Pierce E. A. Patten R. A. Coussa K. Kosai W. A. Radford L. M. Giegerich J. M. Edwards S. M. Johnson S. T. Baur J. A. Roth B. Nosho T. J. De Lyon J. E. Jensen R. E. Longshore 《Journal of Electronic Materials》2004,33(6):509-516
Raytheon Vision Systems (RVS, Goleta, CA) in collaboration with HRL Laboratories (Malibu, CA) is contributing to the maturation
and manufacturing readiness of third-generation, dual-color, HgCdTe infrared staring focal plane arrays (FPAs). This paper
will highlight data from the routine growth and fabrication of 256×256 30-μm unit-cell staring FPAs that provide dual-color
detection in the mid-wavelength infrared (MWIR) and long wavelength infrared (LWIR) spectral regions. The FPAs configured
for MWIR/MWIR, MWIR/LWIR, and LWIR/LWIR detection are used for target identification, signature recognition, and clutter rejection
in a wide variety of space and ground-based applications. Optimized triple-layer heterojunction (TLHJ) device designs and
molecular beam epitaxy (MBE) growth using in-situ controls has contributed to individual bands in all dual-color FPA configurations
exhibiting high operability (>99%) and both performance and FPA functionality comparable to state-of-the-art, single-color
technology. The measured spectral cross talk from out-of-band radiation for either band is also typically less than 10%. An
FPA architecture based on a single-mesa, single-indium bump, and sequential-mode operation leverages current single-color
processes in production while also providing compatibility with existing second-generation technologies. 相似文献
8.
9.
Spectral crosstalk by radiative recombination in sequential-mode, dual mid-wavelength infrared band HgCdTe detectors 总被引:1,自引:0,他引:1
R. A. Coussa A. M. Gallagher K. Kosai L. T. Pham G. K. Pierce E. P. Smith G. M. Venzor T. J. De Lyon J. E. Jensen B. Z. Nosho J. A. Roth J. R. Waterman 《Journal of Electronic Materials》2004,33(6):517-525
For small pixel, infrared (IR) focal plane arrays (FPAs), Raytheon Vision Systems’ architecture for integrated, dual-band
detectors uses the sequential mode of the n-p+-n configuration. There is a single indium bump per pixel, leaving the p+ layer floating, and the operating polarity of the bias selects the spectral sensitivity by reverse-biasing the active p-n
junction. Photogenerated minority carriers in the absorber layer of the forward-biased inactive photodiode are lost through
recombination. This paper is the first report of a new optical crosstalk mechanism that occurs in sequential-mode, dual-band
detectors. In the long-wavelength mode under out-of-band, short-wavelength illumination, radiative recombination yields emission
near the bandgap energy of the short-wavelength absorber layer, resulting in a spurious short-wavelength response that appears
as spectral crosstalk. We present experimental and device modeling results on the spectral crosstalk in molecular-beam-epitaxy-grown
HgCdTe arrays with the cutoff wavelength of both bands in the 4–5-μm range. 相似文献
10.
Tadatoshi Sugio Hideyuki Matsuura Takeshi Matsui Manabu Matsunaga Tatsuya Nosho Shigehiko Kanaya Atsuhiko Shinmyo Ko Kato 《Journal of Bioscience and Bioengineering》2010,109(2):170-173
The sequence context around the AUG initiation codon strongly contributes to the translation initiation step in mammalian and plant cells. Here, we investigated the effect of the three nucleotides immediately upstream of the initiating AUG (positions − 3 to − 1) on the translation efficiency of a reporter gene, β-glucuronidase, in dicotyledonous and monocotyledonous plant cells. 相似文献