Photoconductivity decay in metamorphic InAsP/InGaAs double heterostructures grown on InAsyP1-y compositionally step-graded buffers -: art. no. 071908

Lattice-mismatched InAs0.32P0.68/In0.68Ga0.32As/InAS(0.32)P(0.68) double heterostructures (DH) were grown on compositionally graded InAsyP1-y/In substrates by solid-source molecular-beam epitaxy (MBE) out to a misfit of similar to 1%. The kinetics of carrier recombination were investigated in the nearly totally relaxed MBE-grown DH structures using photoconductivity decay (PCD) measurements. High minority carrier lifetimes of 4-5 mus. close to the radiation limit were measured, indicating the ability of MBE-grown InAsyP1-y buffers in achieving high-electronic-quality, low-band-gap mismatched InGaAs layers. Analysis suggests that very low interface recombination velocities are achieved. A photogenerated carrier diffusion model is presented to explain the initial nonlinear decays observed in PCD data for these heterostructures. (C) 2005 American Institute of Physics.