Investigation of the role of the stress gradient in the pad for silicon nanowire growth by using raman spectroscopy

Focal point height-dependent silicon Raman spectra were taken from silicon nanowires (SiNWs) vertically grown on a patterned Ni-Ti bimetallic strips on Si(100) with a native oxide caused by annealing at 1000 °C The peak position of the silicon optical vibrational mode experiences a large shift in a short spatial interval that corresponds to the thickness of the reactive layer formed by diffusion among the layers. This peak shift indicates the development of stress in the thin reactive layer. This stress acts as the driving force for the vertical growth of SiNWs.