Non-Planckian infrared emission from GaAs devices with electrons and lattice out-of-thermal-equilibrium

Radiation of a cw CO2 laser can be used to excite infrared emission spectra of nearly all molecular gases by adding small amounts of SF6 as a sensitizer. These emission spectra show a thermal equilibrium between vibrational, rotational, and translational states with temperatures up to 1200 K. Temperature profiles of these gases about a focused cw CO2 laser beam are analyzed by Raman spectroscopy. The detection of small amounts of sample and investigations of cw laser-induced chemical reactions are interesting potential applications.

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Aromatic Infrared Emission in Cirrus Clouds

Symposium - International Astronomical Union ◽

10.1017/s007418090012515x ◽

1989 ◽

Vol 135 ◽

pp. 119-128

Author(s):

J. L. Puget

Keyword(s):

Polycyclic Aromatic Hydrocarbons ◽

Energy Distribution ◽

Aromatic Hydrocarbons ◽

Thermal Equilibrium ◽

Molecular Clouds ◽

Infrared Emission ◽

Cirrus Clouds ◽

Mid Infrared ◽

Spectrophotometric Data ◽

Polycyclic Aromatic

We discuss the fraction of the infrared cirrus emission radiated out of thermal equilibrium using the IRAS data. Recent spectrophotometric data (Giard et al., 1988a, 1988b) are presented which confirm that aromatic infrared bands account for at least a fraction of their near and mid-infrared cirrus emission as was suspected from indirect arguments. Large variations of the energy distribution among the IRAS bands are shown to be present in molecular clouds. Abundances of polycyclic aromatic hydrocarbons (PAH's) required to account for the emission are discussed.

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THE SV RATIO IN THERMODYNAMIC PROCESSES

Knowledge International Journal ◽

10.35120/kij28041355i ◽

2018 ◽

Vol 28 (4) ◽

pp. 1355-1360

Author(s):

Ivana Krulj ◽

Gordana Bogdanović

Keyword(s):

Natural Science ◽

Thermal Equilibrium ◽

Scaling Laws ◽

Gravitational Interaction ◽

Scaling Law ◽

Infrared Emission ◽

The Body ◽

Special Place ◽

Thermodynamic Processes ◽

Area And Volume

Thermodynamic processes take special place not just in the physical approach to understanding nature, but in almost every single natural science, and also humanistic ones. The speed of establishing balanced state in a certain thermodynamic system is proportional to ratio between area and volume of its interior bodies. Scaling laws play an important role in analyzing influence of the ratio between bodies' area and volume in thermodynamic systems. In general, scaling laws explore dependency of a certain physical quantity on dimensions' changes. In this work, Galileo's "Two new sciences" is mentioned, in which the geometrical and material enlargements of a body are compared. His mathematical cradle experiments-initiated formulation of scaling laws (so have Kepler's analysis of planets' kinematics and Newtown's description of gravitational interaction done). In the upcoming text, the simplest scaling law is explained-the law of dependency of S/V ratio on a change of body's dimensions. It also includes description of an influence the ratio has on the speed of establishing thermal equilibrium. Cooling and warming processes are described, as well as matching dependencies of their speed on body's area and volume. Considering that there are warm-blooded organisms in organic world, that is, organisms whose temperature does not depend on the temperature of their environment, the description of the model suitable for exploring that phenomenon is given. To be more precise, as energy is being generated on cell level, or, in every part of the organism, heating of the body via microwave and infrared emission is modelled. Comparisons of these two ways of heating are made, followed by dependency of establishing thermal equilibrium on body's dimensions. At the end, it is pointed out how important exploring of the scaling laws is, since they haven't been given a special place in natural science courses, and, generally speaking, belong to many sciences and science disciplines. It is being predicted that scaling laws are going to be explored more intensively, especially having the miniaturization of many devices and creating robots of sub-cell dimensions in mind.

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Detection and Characterization of earth-like Planets

International Astronomical Union Colloquium ◽

10.1017/s0252921100014810 ◽

1997 ◽

Vol 161 ◽

pp. 299-311 ◽

Cited By ~ 22

Author(s):

Jean Marie Mariotti ◽

Alain Léger ◽

Bertrand Mennesson ◽

Marc Ollivier

Keyword(s):

Direct Detection ◽

Contrast Ratio ◽

Angular Size ◽

Physical Nature ◽

Major Axis ◽

Infrared Emission ◽

Space Technology ◽

Semi Major Axis ◽

Earth Like Planets ◽

Visible Wavelengths

AbstractIndirect methods of detection of exo-planets (by radial velocity, astrometry, occultations,...) have revealed recently the first cases of exo-planets, and will in the near future expand our knowledge of these systems. They will provide statistical informations on the dynamical parameters: semi-major axis, eccentricities, inclinations,... But the physical nature of these planets will remain mostly unknown. Only for the larger ones (exo-Jupiters), an estimate of the mass will be accessible. To characterize in more details Earth-like exo-planets, direct detection (i.e., direct observation of photons from the planet) is required. This is a much more challenging observational program. The exo-planets are extremely faint with respect to their star: the contrast ratio is about 10−10at visible wavelengths. Also the angular size of the apparent orbit is small, typically 0.1 second of arc. While the first point calls for observations in the infrared (where the contrast goes up to 10−7) and with a coronograph, the latter implies using an interferometer. Several space projects combining these techniques have been recently proposed. They aim at surveying a few hundreds of nearby single solar-like stars in search for Earth-like planets, and at performing a low resolution spectroscopic analysis of their infrared emission in order to reveal the presence in the atmosphere of the planet of CO H2O and O3. The latter is a good tracer of the presence of oxygen which could be, like on our Earth, released by biological activity. Although extremely ambitious, these projects could be realized using space technology either already available or in development for others missions. They could be built and launched during the first decades on the next century.

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Using the secondary electrons (SE) of SEM with NIST‘s MONSEL-II program to obtain improved linewidth measurements and slope angles of line edges on a MMIC GaAs device

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100167184 ◽

1996 ◽

Vol 54 ◽

pp. 944-945

Author(s):

Richard G. Sartore

Keyword(s):

Integrated Circuits ◽

Plasma Etching ◽

Microwave Integrated Circuits ◽

Monolithic Microwave Integrated Circuits ◽

Thick Gold ◽

Gaas Devices ◽

Source Distance ◽

Margin Of Error ◽

Dimensional Measurements ◽

Barrier Metal

In the evaluation of GaAs devices from the MMIC (Monolithic Microwave Integrated Circuits) program for Army applications, there was a requirement to obtain accurate linewidth measurements on the nominal 0.5 micrometer gate lengths used to fabricate these devices. Preliminary measurements indicated a significant variation (typically 10 % to 30% but could be more) in the critical dimensional measurements of the gate length, gate to source distance and gate to drain distance. Passivation introduced a margin of error, which was removed by plasma etching. Additionally, the high aspect ratio (4-5) of the thick gold (Au) conductors also introduced measurement difficulties. The final measurements were performed after the thick gold conductor was removed and only the barrier metal remained, which was approximately 250 nanometer thick platinum on GaAs substrate. The thickness was measured using the penetration voltage method. Linescan of the secondary electron signal as it scans across the gate is shown in Figure 1.

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