Competition of compressive strain with substrate misorientation in CuPt-type ordered GaInP/AlGaInP quantum wells

Temperature-dependent photoluminescence (PL) measurements are carried out on lattice-matched and compressively strained GaxIn1-xP/(Al0.66Ga0.(34))(y)In1-yP quantum wells (QWs) with CuPt-type long-range (LR) ordering. Experimental data show that compressive strain and substrate misorientation of the QWs affect the degree of LR ordering. The compressive strain competes with the misorientation of 6 off toward [111](A) (denoted as 6 degrees A) significantly. It not only affects the distribution of domains with different degree of LR ordering in the x-y plane but also introduces fluctuation of the degree of LR ordering along the z direction of the QWs, which in turn causes the splitting of PL peaks. A phenomenological model is proposed to account for the experimental phenomena based on the principle of minimum total free energy. The results suggest that 6 degrees A misorientation should not be preferable for compressively strained GaxIn1-xP QWs with LR ordering. (C) 2011 American Institute of Physics. [doi:10.1063/1.3525586]