InGaAs/InP and InAsP/InP quantum well structures on GaAs (100) with a linearly graded InGaP buffer layer grown by gas-source molecular beam epitaxy

A linearly graded InxGa1−xP (x=0.48–1) buffer layer is used for growing a high-quality InP layer on a GaAs substrate. We show that an InxGa1−xP buffer layer is superior to an InyGa1−yAs buffer layer because it is transparent to long wavelengths and allows a less stringent composition control. InGaAs/InP single quantum wells and InAsP/InP multiple quantum wells grown on the InP/InxGa1−xP/GaAs substrate show comparable quality to similar structures grown on InP (100) substrates. Photocurrent spectra for the latter exhibit quantum-confined Stark effect near 1.3 μm.