Extended wavelength opto-electronic devices

Abstract

An improved semiconductor device is provided. The semiconductor device comprises a first layer on a restricted growth surface having a first central region with a transverse dimension D and having a first average lattice constant L.sub.1 within the first central region; a first, last and at least one intermediate transition layers, the transition layers forming a transition region, the transition region disposed above the first layer, the transition region having a vertical thickness T, and where at least one of the intermediate transition layers has average lattice constants between L.sub.1 and a second average lattice constant L.sub.c where the first transition layer has a lattice constant closer to the L.sub.1 than L.sub.c and the last transition layer has a lattice constant closer to the L.sub.c than L.sub.1 ; and a second layer disposed on the transition region, the second layer having a second average lattice constant L.sub.2, the second layer having a second central region having the average lattice constant L.sub.c and an average lattice constant L.sub.3 outside of the second central region, and where L.sub.c does not equal L.sub.3 ; wherein: the transition region has an average fractional change in lattice constant characterized by .kappa. where .kappa.=(D/T) {(L.sub.c -L.sub.1)/L.sub.1 }, where .vertline..kappa..vertline.<18 and wherein a lattice mismatch .vertline.L.sub.c -L.sub.1 .vertline./L.sub.1 .gtoreq.0.0014. Additionally, various preferred semiconductor substrates, transition regions and active regions are discussed.