GROWTH AND CHARACTERIZATION OF COHERENT QUANTUM DOTS GROWN BY SINGLE-CYCLE AND MULTICYCLE METAL-ORGANIC CHEMICAL-VAPOR-DEPOSITION

Very strongly electronically coupled zero-dimensional structures were grown using metal-organic chemical vapour deposition (MOCVD). The meth od is based on formation of first a sheet with InGaAs pyramids on the GaAs (100) surface, and subsequent alternate short-period GaAs-InGaAs deposition with GaAs layer thickness much smaller than the pyramid hei ght. This results in formation of column-like InGaAs structures. Each structure has a characteristic lateral size of similar to 23 nm at the top and is composed of many closely packed InGaAs parts separated by only 2-3 monolayer-thick GaAs barrier layers. Each upper InGaAs part i n a column is progressively larger than the lower parts. The full widt h at half maximum of luminescence of 28 meV at 8 K indicates good aver age uniformity of the electronically coupled dot ensemble. Effective t unability of the emission wavelength at and around 1.3 mu m can be rea lized using this approach.