Site-selection of Si1 −xGex quantum dots on patterned Si(001) substrates

We investigate theheteroepitaxial Si0.5Ge0.5quantum dot site-selection on apatterned Si(001) substrate by continuously varying the underlying substratepattern morphology from pit-in-terrace to quasi-sinusoidal. The pit-in-terrace morphology leads to well-orderedquantum dots centered in the pits over a wide range ofpattern wavelengths. However, for quasi-sinusoidal morphology, when thepattern wavelength is twice the intrinsic lengthscale,quantum dots suddenly bifurcate and shift to form in every saddle point, with high uniformity in size and site occupancy. We compare our results with existingmodels ofquantum dot formation onpatterned surfaces.

Source: Applied Physics Letters - November 8, 2016 Category: Physics Authors: J. M. Amatya and J. A. Floro Source Type: research