Structural and optical characterization of strained and strain-compensated InGaAsP/InP quantum well laser structures

Abstract

InGaAsP/InP strained and strain-compensated multi-quantum wells grown by low pressure metalorganic chemical vapor deposition for fabricating 1.3 μm lasers were characterized by double crystal X-ray diffraction, transmission electron microscopy, atomic force microscopy, cathodoluminescence, and photoluminescence. The quantum wells were compressively strained at 1.14% or 2.55%. Strain-compensated structures were obtained by using appropriately tensile-strained barriers so that the net strain of the multi-quantum well region is approximately zero. It is observed that the sample which had a strain of 2.55% in the wells and which was strain-compensated showed the poorest structural and optical quality. Also, the sample which had a strain of 2.55% and uncompensated showed an inhomogeneous layer growth compared to the sample which had a strain of 1.14%. The results also showed that a quantum well strain of 1.14% can be compensated without affecting the structural and optical quality of the layers.