Naturally formed InxAl1minus;xAs/InyAl1minus;yAs vertical superlattices

摘要

InxAl1minus;xAs/InyAl1minus;yAs vertical superlattices (VS) were naturally formed by phase separation during the growth of InAlAs/InP layers at temperatures in the range 565ndash;615thinsp;deg;C by metalorganic chemical vapor deposition. The VS lies perpendicular to the (001) growth plane. As the growth temperature increased from 565 to 615thinsp;deg;C, the VS decreased in thickness from sim;15 to sim;6 nm, and became less planar and uniform. Transmission electron diffraction results showed the occurrence of CuPthyphen;type ordering in some of the layers. Bandhyphen;gap reduction of sim;300 meV was observed in the InAlAs layers grown at temperatures ranging from 565 to 615thinsp;deg;C. Such a large reduction in bandhyphen;gap energy was attributed to combined effects of the VS and CuPthyphen;type ordering. copy;1996 American Institute of Physics.