Spontaneously forming periodic composition-modulated InGaAsP structures

InGaAsP epitaxial layers, which are obtained in the instability region on I nP (001) and GaAs (001) substrates, are investigated by photoluminescence a nd transmission-electron-microscopy methods. The results are discussed on t he basis of the theory of spinodal decomposition of solid solutions. It is established experimentally that in certain temperature and composition rang es the solid solutions InGaAsP are a system of charged, alternating (in mut ually perpendicular directions [100] and [010]) domains of a solid solution with two different compositions and different lattice constants. The domai n structure is very clearly defined at the surface of the epitaxial film an d becomes blurred in the film near the substrate. The data obtained very li kely show spinodal decomposition of the solid solutions InGaAsP in the test samples. (C) 1999 American Institute of Physics. [S1063-7826(99)0045-6].