Silicon nanowires (SiNWs) were produced by nanosphere lithography and metal assisted chemical etching. The combination of these methods allows the morphology and organization control of Si NWs on a large area. From the investigation of major parameters affecting the etching such as doping type, doping concentration of the substrate, we demonstrate the formation of new Si architectures consisting of organized Si NW arrays formed on a micro/mesoporous silicon layer with different thickness. These investigations will allow us to better understand the mechanism of Si etching to enable a wide range of applications such as molecular sensing, and for thermoelectric and photovoltaic devices.

Adhesion between microgripper end-effector and a nano/micro-object is a main topic for manipulation in microand nanoscale. Tuning this force is a great challenge. Adhesion force is directly linked to the chemical composition and the surface roughness of both, the object and the gripper. Recently, we proposed a multispheres van der Waals force model able to predict this force. The surface used was structured by an array of polystyrene spheres with radii from 35 nm to 2 μm. The experimental pull-off forces have confirmed our model. In this present work, we analyzed other innovating structure such as nonclosed packed polystyrene (PS) spheres and organized Si nanostructures, formed by chemical etching. The adhesion values of the pull-off force measured on these structures were very low (in the range of 2−10 nN) and suggest that these new structures have nonadhesive properties. A new model taking in account the roughness and the organization of the PS spheres and Si nanostructures has been developed to predict these new properties.