Effects of substrate misorientation on the formation and characteristics of self-assembled InP/InGaP quantum dots

Abstract

The structural and optical characteristics of self-assembled InP/InGaP quantum jots grown by low-pressure metalorganic vapor phase epitaxy on GaAs substrates misoriented by 0 degrees, 2 degrees, 5 degrees, 6 degrees, and 35.3 degrees toward(111)A are investigated. The analysis through atomic force microscopy and photoluminescence (PL) shows that the formation of quantum dots strongly depends on the orientation of the substrate. It is seen that large dots are more easily formed on an exactly (001) substrate but, with the increase of the degree of misorientation, the size of dots decreases and the density increases. In addition, the PL emission energy from InP dots is observed to be strongly blue-shifted with the increase in misorientation. From power-dependent PL measurement, the change of PL spectra is observed to be closely related to the size and density of the quantum dots.