Real-time monitoring of InAs/GaAs quantum dot growth using ultraviolet light scattering

We present real-time measurements of surface structure evolution during qua ntum dot growth in InAs/GaAs grown by molecular-beam epitaxy. The measureme nts were made using an ultraviolet light-scattering technique in which the 254 nm line of a mercury lamp is used as the light source. This technique p rovides sensitivity to roughness on lateral lengthscales as low as 154 nm f or our setup. Using this technique, we can detect the onset of quantum dot formation in this system, as indicated by reflection high-energy electron-d iffraction measurements. The continuous increase in the: scattering signal after the dots have formed, is explained in terms of diffusion-limited grow th and ripening of the large islands that coexist with the quantum dots. [S 0163-1829(99)09047-5].