The use of InAs as a substrate for MBE- grown heterojunction with better than 10-3 lattice-matching should make available a range of electronic and photonic heterojuction devices of high mobilities and lower bandgaps than those available on GaAs substrates. Little is known about either the barriers ( Ec, Ev) expected for such heterojunctions or the transport properties of such structures and these will be studied. This is of primary importance to future electrooptical and photonic devices (detectors, lasers and modulators). The bandgaps of materials available which lattice-match to InAs range from 0.35 to 1.2 eV and therefore cover the atmospheric transmission windows out to 2.6 um. Multiple heterojunction layers on InAs substrates may also be of interest for FET and bipolar transistor applications. Schottky barrier and heterojunction behavior (np, pn, nn and pp) will be investigated. The grown layers will be characterized for optical interaction, structural imperfections and for generation-recombination in the bulk and at the interfaces at temperatures down to 80K.
