Room-temperature bandwidth of 2-μm AlInAsSb avalanche photodiodes

The hole dominated avalanche multiplication characteristics of 4H-SiC Separate Absorption and Multiplication avalanche photodiodes (SAM-APDs) were determined experimentally and modeled using a local multiplication model. The 0.5x 0.5mm2 diodes had very low dark current and exhibited sharp, uniform breakdown at about 580V. The data agree with modeling result using extrapolated impact ionization coefficients reported by Ng et al. and is probably valid for electric fields as low as ~0.9MV/cm at room temperature provided that both the C-V measurements and electric field determination in this work are correct. The packaged devices demonstrate a positive temperature coefficient of breakdown voltage for temperatures ranging from 100K to 300K which is a desired feature for extreme environment applications.

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Progress on GaInAsSb And InAsSbP Photodetectors for MiD-Infrared Wavelengths

MRS Proceedings ◽

10.1557/proc-484-135 ◽

1997 ◽

Vol 484 ◽

Cited By ~ 3

Author(s):

Z. A. Shellenbarger ◽

M. G. Mauk ◽

P. E. Sims ◽

J. A. Cox ◽

J. D. Lesko ◽

...

Keyword(s):

Liquid Phase ◽

Epitaxial Growth ◽

Wavelength Range ◽

Room Temperature ◽

Avalanche Photodiodes ◽

Avalanche Photodiode ◽

Avalanche Multiplication ◽

Mid Infrared ◽

Infrared Wavelengths ◽

Liquid Phase Epitaxial Growth

AbstractProgress on mid-infrared photodetectors fabricated by the liquid phase epitaxial growth of GaInAsSb, InAsSbP, and AlGaAsSb on GaSb and InAs substrates is reported. GaInAsSb p/n and p-i-n detectors, InAsSbP p/n detectors and AlGaAsSb/GaInAsSb avalanche photodiode (APD) structures were fabricated. Preliminary results indicate that these devices can have higher detectivity with lower cooling requirements than commercially available detectors in the same wavelength range. Infrared p/n junction detectors made from GaInAsSb and InAsSbP showed cut-off wavelengths of 2.3.μm and 2.8. μm respectively. Room temperature background noiselimited detectivity (D*BLIP) of 4 × 1010 cmHz1/2/W for GaInAsSb detectors and 4 × 108 cmHz1/2/W for InAsSbP was measured. Room-temperature avalanche multiplication gain of 20 was measured on AlGaAsSb/GaInAsSb avalanche photodiodes.

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Dependence of Intergranular Fracture on Boundary Topography and Cohesion

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100071193 ◽

1973 ◽

Vol 31 ◽

pp. 150-151

Author(s):

J. E. Doherty ◽

A. F. Giamei ◽

B. H. Kear ◽

C. W. Steinke

Keyword(s):

Grain Boundary ◽

Room Temperature ◽

Nickel Base Superalloy ◽

Boundary Shear ◽

Room Temperature Ductility ◽

Solid Solution Matrix ◽

Nickel Base ◽

Solution Matrix ◽

Different Levels ◽

Base Superalloy

Recently we have been investigating a class of nickel-base superalloys which possess substantial room temperature ductility. This improvement in ductility is directly related to improvements in grain boundary strength due to increased boundary cohesion through control of detrimental impurities and improved boundary shear strength by controlled grain boundary micros true tures.For these investigations an experimental nickel-base superalloy was doped with different levels of sulphur impurity. The micros tructure after a heat treatment of 1360°C for 2 hr, 1200°C for 16 hr consists of coherent precipitates of γ’ Ni3(Al,X) in a nickel solid solution matrix.

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Hepatocyte Alterations in Guinea Pigs FED Polychlorinated Biphenyls (PCBs), Dibenzodioxins (PCDD), AND DIBENZOFURANS (PCDF)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053085 ◽

1982 ◽

Vol 40 ◽

pp. 56-57

Author(s):

J. N. Turner ◽

D. N. Collins

Keyword(s):

Guinea Pigs ◽

Room Temperature ◽

Dose Group ◽

Methyl Cellulose ◽

Uranyl Acetate ◽

Target Organ ◽

Office Building ◽

Lead Citrate ◽

Control Groups ◽

Cooling Fluid

A fire involving an electric service transformer and its cooling fluid, a mixture of PCBs and chlorinated benzenes, contaminated an office building with a fine soot. Chemical analysis showed PCDDs and PCDFs including the highly toxic tetra isomers. Guinea pigs were chosen as an experimental animal to test the soot's toxicity because of their sensitivity to these compounds, and the liver was examined because it is a target organ. The soot was suspended in 0.75% methyl cellulose and administered in a single dose by gavage at levels of 1,10,100, and 500mgm soot/kgm body weight. Each dose group was composed of 6 males and 6 females. Control groups included 12 (6 male, 6 female) animals fed activated carbon in methyl cellulose, 6 males fed methyl cellulose, and 16 males and 10 females untreated. The guinea pigs were sacrificed at 42 days by suffocation in CO2. Liver samples were immediately immersed and minced in 2% gluteraldehyde in cacadylate buffer at pH 7.4 and 4°C. After overnight fixation, samples were postfixed in 1% OsO4 in cacodylate for 1 hr at room temperature, embedded in epon, sectioned and stained with uranyl acetate and lead citrate.

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Domain Formation in Synthetic Quartz

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100064839 ◽

1971 ◽

Vol 29 ◽

pp. 156-157

Author(s):

Joseph J. Comer

Keyword(s):

Electron Beam ◽

Room Temperature ◽

Domain Formation ◽

Synthetic Quartz ◽

Transmission Electron ◽

Black Spots ◽

Diffraction Mode ◽

Domain Boundaries ◽

Kikuchi Lines ◽

Straight Lines

Domains visible by transmission electron microscopy, believed to be Dauphiné inversion twins, were found in some specimens of synthetic quartz heated to 680°C and cooled to room temperature. With the electron beam close to parallel to the [0001] direction the domain boundaries appeared as straight lines normal to <100> and <410> or <510> directions. In the selected area diffraction mode, a shift of the Kikuchi lines was observed when the electron beam was made to traverse the specimen across a boundary. This shift indicates a change in orientation which accounts for the visibility of the domain by diffraction contrast when the specimen is tilted. Upon exposure to a 100 KV electron beam with a flux of 5x 1018 electrons/cm2sec the boundaries are rapidly decorated by radiation damage centers appearing as black spots. Similar crystallographio boundaries were sometimes found in unannealed (0001) quartz damaged by electrons.

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A Liquid Nitrogen Cooled Stage for STEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100052237 ◽

1974 ◽

Vol 32 ◽

pp. 444-445

Author(s):

Louis T. Germinario

Keyword(s):

Electron Microscope ◽

High Resolution ◽

Liquid Nitrogen ◽

Room Temperature ◽

Objective Lens ◽

Thermal Drift ◽

Specimen Holder ◽

Resolution Capability ◽

Focal Position

A liquid nitrogen stage has been developed for the JEOL JEM-100B electron microscope equipped with a scanning attachment. The design is a modification of the standard JEM-100B SEM specimen holder with specimen cooling to any temperatures In the range ~ 55°K to room temperature. Since the specimen plane is maintained at the ‘high resolution’ focal position of the objective lens and ‘bumping’ and thermal drift la minimized by supercooling the liquid nitrogen, the high resolution capability of the microscope is maintained (Fig.4).

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Cryogenic atomic force microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100084570 ◽

1991 ◽

Vol 49 ◽

pp. 54-55

Author(s):

K. A. Fisher ◽

M. G. L. Gustafsson ◽

M. B. Shattuck ◽

J. Clarke

Keyword(s):

Room Temperature ◽

Rapid Freezing ◽

Cryogenic Temperatures ◽

Soft Or ◽

Electrically Conductive ◽

Force Microscopy ◽

Flexible Molecules ◽

Advantages And Disadvantages ◽

Atomic Force ◽

Chemical Perturbation

The atomic force microscope (AFM) is capable of imaging electrically conductive and non-conductive surfaces at atomic resolution. When used to image biological samples, however, lateral resolution is often limited to nanometer levels, due primarily to AFM tip/sample interactions. Several approaches to immobilize and stabilize soft or flexible molecules for AFM have been examined, notably, tethering coating, and freezing. Although each approach has its advantages and disadvantages, rapid freezing techniques have the special advantage of avoiding chemical perturbation, and minimizing physical disruption of the sample. Scanning with an AFM at cryogenic temperatures has the potential to image frozen biomolecules at high resolution. We have constructed a force microscope capable of operating immersed in liquid n-pentane and have tested its performance at room temperature with carbon and metal-coated samples, and at 143° K with uncoated ferritin and purple membrane (PM).

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