Growth mode of tensile-strained Ge quantum dots grown by molecular beam epitaxy
Artikel i vetenskaplig tidskrift, 2017
Growth mode of tensile-strained Ge quantum dots on different III-V buffers by molecular beam epitaxy is studied by a combination of reflection high-energy electron diffraction, atomic force microscopy and transmission electron microscopy. The Ge-QDs growth on the InAlAs buffer lattice matched to InP and on InAs buffer on GaSb follows the Volmer-Weber growth mode with round Ge QDs and no Ge wetting layer, while it obeys the Stranski-Krastanov growth mode on GaSb, AlSb and AlGaSb on GaSb substrates, showing rectangular shaped platelets and a clear Ge wetting layer. The discovery of the Volmer-Weber growth mode is essential to avoid forming a wetting layer and the subsequent antiphase-domain defects when capping III-Vs on Ge-QDs, important for potential optoelectronic applications.