Silicon-Germanium Nanowires: Chemistry and Physics in Play, from Basic Principles to Advanced Applications

The different employed growth techniques for silicon-germanium (SiGe) nanowires, their morphology and structural properties were discussed. Significant progresses toward a precise control of the NWs composition were subsequently made in chemical vapor deposition using an appropriate gas inlet ratio in an optimum temperature range or tuning the total growth pressure. Long and straight, without significant tapering, SiGe NWs were obtained through the use of additional gases, other than the usual precursor. Regarding the morphology both axial and radial heterostructures have been reported so far. When laser ablation and CVD techniques were combined, axially modulated SiGe NWs of different diameters were produced. A better control of the interface sharpness, of the order of 1nm, has been then reached combining vapor-liquid-solid (VLS) and vapor-solid-solid (VSS) growth. It is clear that SiGe nanowires will play an important role in the next generation of advanced miniaturized devices.