Diffusion Diodes

HgCdTe photodiode performance for the most part depends on high quantum efficiency and low dark current density (83,84) as expressed by equations 23 and 25. Typical values of at 77 K ate shown as a function of cutoff wavelength in Figure 16 (70). HgCdTe diodes sensitive out to a wavelength of 10.5 p.m have shown ideal diffusion current limitation down to 50 K. Values of have exceeded 1 x 10 . Spectral sensitivities for... 

The heart of the energy-dispersive spectrometer is a diode made from a silicon crystal with lithium atoms diffiised, or drifted, from one end into the matrix. The lithium atoms are used to compensate the relatively low concentration of grown-in impurity atoms by neutralizing them. In the diffusion process, the central core of the silicon will become intrinsic, but the end away from the lithium will remain p-type and the lithium end will be n-type. The result is a p-i-n diode. (Both lithium-... 

The start of the solid-state electronic industry is generally recognized as 1947 when Bardeen, Brattain, and Shockley of Bell Telephone Laboratories demonstrated the transistor function with alloyed germanium. The first silicon transistor was introduced in 1954 by Texas Instruments and, in 1956, Bell Laboratories produced the first diffused junction obtained by doping. The first-solid state transistor diodes and resistors had a single electrical function and were (and still are) known as discrete devices. 

Samples were characterized by FTIR spectroscopy with a Perkin Elmer (Spectrum BX) spectrometer using KBr pressed disks as matrices. The DRIFT experiments were carried out with a Broker IFS 55 spectrometer equipped with a Thermo Spectra Tech reacting cell. UV-vis Diffuse Reflectance spectra were recorded on a Perkin Elmer Lambda 45 spectrophotometer equipped with a diffuse reflectance attachment. Raman spectra were collected with Perkin Elmer system 2000 NIR FT-Raman using as excitation radiation the 5th harmonic of a diode pumped Nd YAG laser (1065 nm). 

Willason and Johnson [53] have described a modified flow-injection analysis procedure for ammonia in seawater. Ammonium ions in the sample were converted to ammonia which diffused across a hydrophobic membrane and reacted with an acid-based indicator. Change in light transmittance of the acceptor steam produced by the ammonia was measured by a light emitting diode photometer. The automated method had a detection limit of 0.05 xmol/l and a sampling rate of 60 or more measurement per hour. 

If the transport were dominated by diffusion of neutrals, one would have a lifetime expression differing from (99) by having D0 instead of D+ and a much smaller R instead of Rc. The mean diffusion distance before capture would be (D0t)1/2, still typically of the order of a micron. However, we shall not consider this case seriously because the variation of the profiles with diode bias clearly showed transport by H+ to be usually dominant. 

F Pschenitzka and JC Sturm, Three-color organic light-emitting diodes patterned by masked dye diffusion, Appl. Phys. Lett., 74 1913-1915, 1999. 

A Schottky diode is always operated under depletion conditions flat-band condition would involve giant currents. A Schottky diode, therefore, models the silicon electrolyte interface only accurately as long as the charge transfer is limited by the electrode. If the charge transfer becomes reaction-limited or diffusion-limited, the electrode may as well be under accumulation or inversion. The solid-state equivalent would now be a metal-insulator-semiconductor (MIS) structure. However, the I-V characteristic of a real silicon-electrolyte interface may exhibit features unlike any solid-state device, as... 

Figure 8.5. Palm of the hand. Fluorescence spectrum (Fb-mode, full line) and diffuse reflectance absorption spectrum (dashed line, normalized to X = 700 nm, reference filter paper) measured with a sensitized diode array spectrometer.

Figure 8.7. Delayed fluorescence and diffuse reflectance transient absorption spectroscopy on scattering substrates. Example terthicnyl on silica gel excited with = 354 nm (neodymium/yttrium-aluminum-garnet) (Nd/YAG) laser pulse of 10 nsec, 20 mj), recorded with a gated diode array spectrometer.

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