FORMATION OF COHERENT SUPERDOTS USING METAL-ORGANIC CHEMICAL-VAPOR-DEPOSITION

We demonstrate direct growth of electronically coupled zero-dimensiona l structures forming a super-quantum dot using metal-organic chemical vapor deposition. After the first sheet with InGaAs pyramids is formed on GaAs surface, alternate short-period GaAs-InGaAs deposition leads to spontaneous formation of layered structures driven by the energetic s of Stranski-Krastanow growth. As a result columnlike InGaAs structur es each having a characteristic lateral size of similar to 23 nm at th e top and composed of many closely packed InGaAs parts are formed. The full width at half maximum of superdot luminescence of 28 meV at 8 K indicates good average uniformity of the superdot ensemble. Absorption is found to be resonant with luminescence. (C) 1996 American Institut e of Physics.