There is a great interest in high speed (5 ns) light detection in the 1.7 to 2.0 micron spectral range. Applications include gas monitoring, downhole logging, atmospheric transmission, and active optical proxity sensing. Although semiconductor photodiodes (inas, insb, pbs, pbse, etc.) are available, they have slow response and lack sensitivity. Epitaxx proposes to develop a novel method to fabricate planar ingaas/inasp photodiodes for this spectrum. These in(.64)ga(.36)as/inas(.21)p(.79) diodes, which respond from 1.1 micron to 1.98 micron, will be grown on an inp substrate via a compositionally graded buffer layer with epitaxx's vapor phase epitaxy (vpe) process. Five prototype photodiodes will be delivered at the end of the phase i program. Performance goals are: quantum efficiency (1.93 micron) - 50%, dark current (-iv) - 100 na, breakdown voltage 100 ua) - 10v, rise/fall time (10-90%) - 5 ns, active diameter 500 microns. These room temperature specifications are superior to anything commercially available. Frequency measurments will be performed by professor gerald herskowitz (stevens). The phase ii program would involve development of packaging techniques for thermoelectric cooled detectors, linear arrays, as well as extension to longer wavelengths (3 micros) and potential development of an avalanche photodiode for 1.93 microns.
