Formation of self-organized quantum dot structures and quasi-perfect CuPt-type ordering by gas-source MBE growth of (GaP)/sub n/(InP)/sub n/ superlattices

(GaP)/sub n/(InP)/sub n/ short period superlattices (SLs) are grown on GaAs(N11) substrates by gas-source MBE. Transmission electron microscopy observations show that the SLs grown on GaAs(311)A and (411)A have dot structures with a size of about 10-20 nm. Photoluminescence (PL) peak energies are greatly dependent on substrate orientation and monolayer number n. On the other hand, the (GaP)/sub 1/(InP)/sub 1/ SLs grown on (111) have no composition modulation and have quasiperfect CuPt-type ordering along the [111] growth direction. The PL peak energy is 321 meV lower than that of disordered InGaP alloy. Self-organized (GaP)/sub n/(InP)/sub m/ SL(dot/barrier)/In/sub 0.49/Ga/sub 0.51/P(barrier) quantum dot structures exhibit strong 77 K PL with a full width at half maximum of about 70 meV.