Nanometer Thick Membranes as Substrates for InAs Growth

We extended this technique from Ge self-assembled structures to the group of III-V semiconductors. In a first work [6], self-assembled InAs growth on freestanding Si membranes was investigated. Therefore, SIO samples were pre-patterned to obtain freestanding Si membranes and overgrown using III-V molecular beam epitaxy (MBE). We find that the InAs deposition influences the compliant Si membrane and the InAs island formation changes from the fixed parts to the freestanding parts. The strain transfer of the islands causes a buckling up of the freestanding membrane. Furthermore, the InAs island density decreases on top of the freestanding parts in comparison to fixed, ridged areas of the sample. Diffraction experiments in combination with finite element calculations allow the investigation of the InAs island strain state. The results indicate that the strain relaxation of the islands depends on the membrane position.