NSL is a useful patterning technique for fabricating periodically ordered nanostructures. Large-area patterns can be easily obtained through self-assembled nanospheres, and the periodicity and the size of the nanopits can be adjusted using different process parameters.

Results obtained by atomic force microscopy and cross-sectional transmission electron microscopy show that 3D ordering was achieved in the Ge QDCs with an areal dot density of 1.2 × 1010 cm–2, and that the lateral and the vertical interdot spacing were ∼10 and ∼2.5 nm, respectively.

Wavefunction overlap

Thanks to the small inderdot spacings, the samples are particularly suitable for investigating the behavior of coupled quantum dot ensembles and related device applications.

The study demonstrates further progress in site-controllable growth of high-density ordered nanostructures. NSL pit-pattern assisted growth of Ge quantum dots is also applicable for other material systems, such as InGaAs and InP quantum dots.

More details can be found in the journal Nanotechnology.