Novel nanostructure architectures

We combine self-assembled island growth with in situ and ex situ selective etching techniques to create advanced semiconductor nanostructure architectures. Such architectures include lateral InAs/GaAs quantum dot molecules and unstrained inverted GaAs/AlGaAs quantum dots (QDs) with photoluminescence (PL) peak linewidths as narrow as 8.9 meV. Micro-PL of single GaAs/AlGaAs QDs reveals well-behaved and sharp exciton emission lines in the red spectral range, which renders these novel nanostructures interesting candidates for future coherent optical investigations. Furthermore, we overgrow self-assembled Ge islands with a thin Si cap layer and use standard e-beam lithography and reactive ion etching to define mesa structures on the surface. The SiGe island core is then selectively etched away, which leaves ultra-thin free-standing Si bridges as remainders on the surface. Such thin Si bridges present an alternative route to produce SiGe-free Si-on-nothing (SON) for advanced complementary metal oxide semiconductor (CMOS) technology.