Abstract

The current trends in infrared detectors are principally towards larger electronically addressed arrays and towards reduced cryogenic cooling requirements. In the UK the research activities have been mainly on hybrids of Cd_xHg_1–xTe (CMT) and of ferroelectric materials on silicon. Large two-dimensional arrays and long linear arrays of CMT are presently fabricated in LPE material by the “loophole" interconnect technology. Results are presented for linear formats up to 1024 elements and for two-dimensional arrays of 128 × 128 elements. It is anticipated that loophole technology will be supplemented at some time in the future by a technology using MOVPE-grown heterostructures, so that the operating temperature of photon detectors can be increased by means of optical concentration or non-equilibrium operation. The former is described in terms of an individual field lens concentrator and the latter is illustrated by recent results on CMT and InSb/In_1–x Al_xSb heterostructures. The heterostructure devices, as well as producing significantly improved RoA, exhibit strong negative resistance effects at temperatures from 190 K upwards. Recent results of 128 × 256 arrays of uncooled ferroelectric hybrids fabricated by solder-bump bonding show very promising performance.

© 1994 IEEE