Laser stimulated selective area growth of quantum dots

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Abstract
We report on the selective area growth of InAs quantum dots on GaAs by ultraviolet (UV) laser stimulated organometallic vapor phase epitaxy. At the low substrate temperature of 435 °C, exposure to a 248.2 nm continuous wave laser beam enhances the InAs growth rate by approximately 30%, causing the transition from two-dimensional (2D) to 3D growth mode to occur in the laser stimulated region only. Photoluminescencespectra from the UV laser stimulated growth region show both wetting layer and quantum dotluminescence, whereas only the wetting layer peak is present in the spectra from the dark grown regions. A photoluminescence map shows good spatial agreement between the region exhibiting quantum dotluminescence and the UV stimulated spot size. Since no quantum dot peak shifts are detected, but the luminescence intensity increases towards the center of the region stimulated with the Gaussian UV beam, we conclude that the island density rather than island size distribution is influenced by the UV intensity.