Effect of strain in In1-x-yAlyGaxAs/In0.523Al 0.477As QW system on InP substrate

Abstract

One of the most significant effects of strain in semiconductor is the reshaping of the valence band which results in the reduced valence band density of states. This effect is being exploited in strained QW lasers. In the present study, a quaternary system In1-x-yAlyGaxAs/In0.523Al 0.477As on InP has been studied. Effects of variation of x and y on optical gain and current density have been calculated. This system was chosen as it can be easily tuned to 1.06 μm wavelength application by properly selecting x and y. The optical gain increases with x for a fixed value of y, whereas it decreases with positive strain, while increases with negative strain. Current density reduces drastically from its unstrained value of 900 A/cm2 to about 380 A/cm2 and less for various strains and gallium compositions. The variations in gain and current density for 1.06 μm wavelength emission for different strains and x values were also studied. It was observed that gain and current density have peaks at x=0.25. The above calculations were done for single QW of 100 Å width.