Extended wavelength lasers having a restricted growth surface and graded lattice mismatch

摘要

An improved semiconductor structure is provided. The semiconductor structure comprises a first layer, the first layer having a restricted growth surface having a region with a transverse dimension D, the first layer having a first lattice constant L1; 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 transition layers has lattice constants between L1 and a second lattice constant L2 where the first transition layer has a lattice constant closer to the L1 than L2 and the last transition layer has a lattice constant closer to the L2 than L1; and a second layer disposed on the transition region, the second layer having the second lattice constant L2; wherein: the transition region has an average fractional change in lattice constant characterized by kappa where kappa =D/T){(L2-L1)/L1}, where 0<| kappa |/=2 mu m.