Formation of coherent superdots using metal-organic chemical vapor deposition

We demonstrate direct growth of electronically coupled zero-dimensional 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 energetics of Stranski–Krastanow growth. As a result columnlike InGaAs structures each having a characteristic lateral size of ∼23 nm at the 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.