Showing papers on "Responsivity published in 1978"
TL;DR: An analysis of sources of error and residual uncertainties shows that the over-all precision of this type of radiometer is at least 0.5% for a power level of 50 microW.
Abstract: The fabrication and principal characteristics of an electrically calibrated absolute radiometer are described. The receiver substrate incorporates an evaporated chromium–nickel thermopile, an electrical shield, a copper thermal diffuser disk, an evaporated chromium electrical heating element, and a goldblack absorber. All insulating layers are evaporated silicon monoxide; the thermopile and heater are made by a photoetching process. The performances of several radiometers are discussed. For example, a 28-junction version has a responsivity and NEP of 93 mV/W and 50 nW, respectively, in air, with a time constant of 15 sec and a surface responsivity uniform to better than 1%. The radiometers require only a few corrections of small magnitude. An analysis of sources of error and residual uncertainties shows that the over-all precision of this type of radiometer is at least 0.5% for a power level of 50 μW. Comparative radiometric measurements are described that support this claim.
20 citations
TL;DR: In this paper, the responsivity of tungsten-nickel point contact diodes for the CO2 laser is investigated as functions of the contact pressure and the oxide thickness on the nickel post.
Abstract: The responsivity of the tungsten-nickel point contact diodes for the CO2 laser is investigated as functions of the contact pressure and the oxide thickness on the nickel post in order to determine the detection mechanisms of point contact MIM diodes at 10.6 µm. The data are compared with the current-temperature (I–T) characteristics and the theory based on the equivalent circuit model. A comparison of the above data and the I–T characteristics indicates that the point contact MIM diode acts as a tunnel diode. It is confirmed, from a comparison of the above data and the theory based on the equivalent circuit model, that the MIM diode operates as a square-law detector for the CO2 laser.
17 citations
TL;DR: In this paper, the speed of Ge submillimetre detectors with the aid of a pulsed n-InSb Landau emitter was investigated and it was shown that the capture cross-section does not decrease appreciably with increasing impurity concentration up to 2 × 1015 impurities per cm3.
15 citations
TL;DR: In this article, donor-doped heteroepitaxial In0.84Ga0.16As0.34P0.66 layers were used to construct self-filtering infrared detectors with a responsivity of 0.46 A/W at a wavelength λ=1.05 μm and a corresponding external quantum efficiency ηx=0.54.
Abstract: Acceptor‐doped heteroepitaxial In0.84Ga0.16As0.34P0.66 layers grown on donor‐doped InP substrates were used to construct self‐filtering infrared detectors with a responsivity of 0.46 A/W at a wavelength λ=1.05 μm and a corresponding external quantum efficiency ηx=0.54.
15 citations
06 Jun 1978
TL;DR: In this article, a low frequency D* of 2 x 109 cm Hz /W has been measured for the polymer PVF2, which is a competitive pyroelectric material for detector arrays using CCD signal processors.
Abstract: Pyroelectric detectors offer the advantages of room temperature operation and wide spectral response. High performance requires good thermal design of the detector and its mounting structure to maximize low frequency responsivity and to minimize temperature noise. The intrinsic detector noise is caused by dielectric losses. In the crystalline ferroelectrics, such as Sr 0.5 Ba 0.5 Nb2O6 (SBN) and LiTaO3, dielectric loss tangents on the order of 0.0003 have been obtained and a intrinsic detector noise may be limited by material impurities. A low frequency D* of 2 x 109 cm Hz /W has been measured for these materials. At these loss tangent values, temperature noise and preamplifier noise for both JFET and CCD amplifiers presently limit performance. Despite its lower pyroelectric coefficient, the polymer PVF2 is a competitive pyroelectric material for detector arrays using CCD signal processors.© (1978) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
12 citations
TL;DR: The two-state model is presented, which is based on the idea that a response-producing system can only exist in one of two states and gives a simple, testable meaning to Q, the semi-saturation intensity, and it leads to increment threshold functions which closely resemble those that have been reported for certain retinal responses.
12 citations
TL;DR: In this article, the spectral responsivity of p-type silicon has been measured using HF, HCl, HBr, H2O and CO2 lasers in the 2.5-33 mu m range.
Abstract: Experimental measurements of the spectral responsivity of (100) and (111) orientated, p-type silicon has been made, using HF, HCl, HBr, H2O and CO2 lasers, in the 2.5-33 mu m range. The high responsivity observed at 33 mu m is explained by reference to the band structure of p-type silicon.
8 citations
TL;DR: In this article, the authors describe a P-type lead telluride detector with a resistance area of 10 cm2 at 180 K and a black body detectivity of 6×109 cm Hz.
Abstract: Lead telluride detector arrays have been made by diffusing indium into arsenic-doped p-type lead telluride. Planar devices have a resistance-area product R0A ? 10 ? cm2 at 180 K and a black body detectivity (D* 500 K) ? 6×109 cm Hz? W?1 a typical array showing a responsivity variation of ±20%. The temperature variation of R0A is consistent with an abrupt junction model with an Auger-limited lifetime.
7 citations
TL;DR: In this article, the parameters influencing the operation of a metal-insulator-metal pointcontact diode are discussed, and it is shown that the responsivity of the diode increases with increasing oxide film thickness.
Abstract: The parameters influencing the operation of a metal-insulator-metal pointcontact diode are discussed. Analyticl results show that the responsivity of the diode increases with increasing oxide film thickness. Oxide films of about 12 A thickness can be obtained on nickel by anodic, oxidation.
7 citations
TL;DR: Gallium arsenide electroabsorption avalanche photodiode (EAP) detectors have been fabricated in n - n(+) GaAs waveguides and have been used to detect analog signals with a distortion less than 6%.
Abstract: Gallium arsenide electroabsorption avalanche photodiode (EAP) detectors have been fabricated in n - n(+) GaAs waveguides. Since these EAP detectors respond to wavelengths beyond the normal absorption edge of GaAs, due to the Franz-Keldysh effect, they have been used to detect the below band gap radiation from GaAs lasers and the 1.06-mum radiation from Nd:YAG lasers. The measured absorption and responsivity at these wavelengths suggest a number of applications. These EAP devices have been used to detect analog signals with a distortion less than 6%. Methods for utilizing them in time- and frequency-demultiplexing applications are also described.
7 citations
TL;DR: In this paper, a silicon device with an optical threshold, which can operate as a digital optical switch, is presented, and a good correlation between theory and the experimental results is obtained.
Abstract: This paper presents a silicon device (m.i.s.t.), with an optical threshold, which can operate as a digital optical switch. Its operation and characteristics are presented. A good correlation between theory and the experimental results is obtained. The responsivity and sensitivity of 0.9 AW?1 and 3.9 × 10?4 mA/?V are obtained, respectively. Possible applications in fast optical digital isolation and in optical communication systems are envisaged.
TL;DR: The constant-amplitude, 600-MHz beat note of a 2-mW He-Ne laser is used to measure the rms current delivered by silicon photodiodes at 600 MHz and it is found that this current first rises with increasing radiant power, saturates, and then begins to decrease at average irradiances greater, similar 100 W cm(-2), even though the direct (or average) current remains linear with radiant power.
Abstract: We have used the constant-amplitude, 600-MHz beat note of a 2-mW He–Ne laser to measure the rms current delivered by silicon photodiodes at 600 MHz We find that this current first rises with increasing radiant power, saturates, and then begins to decrease at average irradiances ≳100 W cm−2, even though the direct (or average) current remains linear with radiant power We have also scanned across the faces of the diodes; we find that uniform dc responsivity need not imply uniform 600-MHz responsivity and that saturation of rf responsivity takes place first in regions of high dc responsivity The response of photodiode at 600 MHz may drop an order of magnitude at an average irradiance of ∼1000 W cm−2; we have observed that the impulse response at roughly the same irradiance is accordingly lengthened
TL;DR: In this paper, a very fast noise-immune uncooled photodetector was developed on the basis of the intraband photoconductivity, which was found to have a time resolution of 2×1010 sec and an output voltage up to 8 V.
Abstract: A new very fast noise-immune uncooled photodetector was developed on the basis of the intraband photoconductivity. The detector was found to have a time resolution of 2×1010 sec and an output voltage up to 8 V. The dependence of the relative photoconductivity Δσ /σ on the carrier density was determined at room temperature at various wavelengths. The responsivity of the photodetector was determined as a function of the wavelength, voltage, and illumination intensity.
TL;DR: A Te-Se-CdO layer structure has been fabricated by epitaxial growth of a selenium film on a monocrystalline tellurium substrate, followed by deposition of the counterelectrode by reactive sputtering from a cadmium target in the presence of a trace of air as mentioned in this paper.
Abstract: A Te-Se-CdO layer structure has been fabricated by epitaxial growth of a selenium film on a monocrystalline tellurium substrate, followed by deposition of the counterelectrode by reactive sputtering from a cadmium target in the presence of a trace of air. Examination by RHEED has shown the counterelectrode to be CdO in polycrystalline form and the selenium film to be monocrystalline. The structures were found to give a maximum photovoltaic responsivity near 550 nm, at which wavelength the quantum efficiency was around 60% for a CdO thickness of 0.2 micron. The responsivity was affected by the CdO film thickness and the contacts to it but was insensitive to conditions relating to the selenium film, with variations in the thickness up to 10 microns, in the orientation between the (0001) and\((10\overline 1 0)\) planes and in the polishing conditions of the tellurium stustrate. Values of equivalent series and shunt resistance were determined from output current-voltage results by curve fitting and the shunt resistance was found to vary inversely with illuminance.
TL;DR: In this article, a model based on thermionic and tunnel currents flowing between a hemispherical and a plane electrode is presented to explain the characteristics of responsivity with electrical and mechanical variations.
Abstract: Point-contact whisker diodes have been used to detect 337 mu m radiation giving responsivities up to 1000 V W-1. The respective merits of metal-insulator-metal and metal-insulator-semiconductor diodes are examined. To explain the characteristics of responsivity with electrical and mechanical variations, a model is presented based on thermionic and tunnel currents flowing between a hemispherical and a plane electrode.
01 Jan 1978