Photoconductor array

At low background flux this gives the temperature dependence of the Z9 shown in Eigure 4. At high flux, the Z9 equation (eq. 37) reduces to equation 12 except for a factor of (2) which is a result of the random recombination process not present in diodes. The scene sensitivity of a scanning photoconductor array infrared camera is ca 0.15°C. 

At the time of the ESA Call for Proposal, there was no detector avmlable in Europe for the long wavelength channel. A specific development was undertaken at the Laboratoire frifrarouge du CEA-LETI in Grenoble. It is a photoconductor array in Si Ga hybridized by Indiiun bumps to a direct voltage readout circuit. It has 32 X 32 pixels, a 100 /joa pitch with a thickness of... 

The Space Infrared Telescope Facility (SIRTF) is our first opportunity to use hi performance infrared arrays on a cooled telescope, where they can reach sensitivity leveb determined only by the environment of the earth in space - that is, by emissions from the zodiacal doud, the Milky Way, or distant galaxies. From space, we are no longer restricted in spectral coverage. To increase the power of SIRTF and to provide a reasonable match of capabilities across its operating range, the MIPS (Multiband Imaging Photometer for SIRTF) team has imdertaken the development of far infrared arrays. This effort has produced the first high performance far infrared photoconductor array evex built. 

A plurality of photo-conductors 10 of HgCdTe form a focal plane array. Each photoconductor comprises a photon collection aperture 12, a confinement region 14 and an overlap metal layer 32. The metal layer 32 forms a common electrode on one side of the aperture and an individual electrode on the other side of the aperture. 

Fig. 21. The output current ID from an elemental integrated-image sensor as a function of the incident photon flux N. The experimental points were obtained when the sensor was addressed individually ( ) and as part of an array (O). It is found that / N% . The photosensor area was 1.4 X 10 3 cm2. The full line was calculated from the individual characteristics of the FET and the a-Si H photoconductor. (From Snell et al. (1984).]...

Some of the photoconductor transducers mentioned in the previous section can also he fabricated into linear arrays for use in Ihe infrared region. 

Fig. 6.8a and b. The use of CCD registers for TDI. (a) IR active CCD register (monolithic focal plane array with photogeneration in the register), (b) Direct injection with Si parcel in series out CCD register hybrid with IR photodiodes or monolithic with silicon IR extrinsic photoconductors... 

Most spectrometers use tungsten-halogen lamps with quartz windows. Cells for absorption measurements are usually quartz or fused silica transparent up to about 3000 nm. Cell lengths vary from 0,1 to 10 cm. Detectors range from PbS and PbSe photoconductors to InSb and InAs photodiodes. Array detectors, such as InGaAs detectors, have also become available for the region. Several commercial UV-visible spectrophotometers are designed to operate from 180 to 2500 nm and can thus be used to obtain NIR spectra. 

The process for a laser printer is similar except for the fact that the image is written onto the photoconductor directly by a laser or a diode array. If the toner particles are fused directly onto the photoconductor instead of transferring them onto paper the photoconductor can be used as an offset printing master [4]. 

Photoconductor Devices. Photoconductive detectors (3) used for infrared imaging are arrays similar to the basic structure in Figure 1. The (Hg,Cd)Te is thinned to an appropriate thickness through a combination of sawing and mechanical polishing, chemically treated to remove residual... 

Development of the new infrared arrays is currently under way (see Table H for their general characteristics). These devices are fabricated on the same lines as the previous one i.e. detection in gaUium-doped silicon photoconductors, readout circuits achieved in silicon NMOS technology, hybridization of these two sub-assemblies by indium bumps. 

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