Photoreflectance study of the interdiffusion effects in the InGaAsP-based quantum well laser structures

Photoreflectance spectroscopy has been used to study interdiffusion effects of dielectric-capped, rapid-thermal-annealed InGaAsP-based quantum well laser structures grown by gas source molecular beam epitaxy. Post-growth modification-induced changes of the quantum well shape influence its energy levels. For the processed laser structures a blue shift of ground and excited state transitions has been observed. It has been found that the energy difference between the two lowest heavy hole levels decreases approximately linearly with the blue shift of the ground state transition.