SELF-ORGANIZED GROWTH OF 3-DIMENSIONAL QUANTUM-DOT CRYSTALS WITH FCC-LIKE STACKING AND A TUNABLE LATTICE-CONSTANT

The self-organization of pyramidal PbSe islands that spontaneously for m during strained-layer epitaxial growth of PbSe/Pb1-xEuxTe (x = 0.05 to 0.1) superlattices results in the formation of three-dimensional qu antum-dot crystals. In these crystals, the dots are arranged in a trig onal lattice with a face-centered cubic (fcc)-like A-B-C-A-B-C vertica l stacking sequence. The Lattice constant of the dot crystal can be tu ned continuously by changing the superlattice period. As shown by theo retical calculations, the elastic anisotropy in these artificial dot c rystals acts in a manner similar to that of the directed chemical bond s of crystalline solids. The narrow size distribution and excellent co ntrol of the dot arrangement may be advantageous for optoelectronic de vice applications.