Site-controlled droplet epitaxy of GaAs quantum dots by deposition through shadow masks Available to Purchase

Droplet epitaxy is a versatile method for fabricating nanostructures, but the standard process relies on spatially random droplet formation resulting in poor control of the position of the final nanostructure. The authors demonstrate site-controlled droplet formation utilizing local Ga deposition combined with self-assembled droplet formation. The local Ga deposition is realized by employing a shadow mask with small apertures. Our experiments show that out-diffusion of Ga from the aperture area is important and can be minimized by creating a Ga saturated surface before depositing through the mask. The effects of Ga precoverage, Ga amount for droplet formation, and droplet formation temperature on size, height, and density of droplets have been investigated. With optimized parameters, the authors were able to generate a single droplet per aperture with over 90% probability.