The growth of Ga0.52In0.48P and Al0.18Ga0.34In0.48P on lens-shaped GaAs substrates by metalorganic vapor phase epitaxy

The substrate orientation dependence of ordering of the group III-sublattice in epitaxial Ga_0.52In_0.48P and Al_0.18Ga_0.34In_0.48P has been studied on metalorganic vapor phase epitaxy (MOVPE) overgrown lens-shaped GaAs substrates centered around the (100). The photoluminescence peak wavelength from the Ga_0.52In_0.48P and Al_0.18Ga_0.34In_0.48P demonstrates a novel “saddle”-shaped mirror plane symmetry with respect to the [011] and [01 1 ¯ https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003069638/440efdcf-c2ed-414a-bdad-7c98e059177f/content/eq369.tif"/> ] crystallographic axes. Ordering of the group-III sub-lattice is optimized on growth planes oriented (100) 5° toward [01 1 ¯ https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003069638/440efdcf-c2ed-414a-bdad-7c98e059177f/content/eq370.tif"/> ] and [0 1 ¯ https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003069638/440efdcf-c2ed-414a-bdad-7c98e059177f/content/eq371.tif"/> 1], as indicated by the maximum wavelength observed there. Disordering is indicated by a gradual decrease in the luminescence wavelength of approximately 40nm as the growth plane approaches orientations of 20° off the (100). Hence, the ordering does not demonstrate a simple monotonic decrease with orientation off the (100). These results are duplicated by growth on planar substrates of select orientations off the (100). The good compositional uniformity of In on the lenses is determined by x-ray diffractometry.