Depth-Detection Methods for CNT Manipulation and Characterization in a Scanning Electron Microscope

Current research work on the development of a nanorobot station for the manipulation and characterization of carbon nanotubes is presented. Therefore two nanorobots are cooperating in the vacuum chamber of a scanning electron microscope (SEM). One robot is carrying a nanogripper and is used for the coarse positioning. The second robot serves as sample holder and realizes the fine positioning. In the course of automatic handling tasks, depth-detection within the SEM is required. Two different methods for the z-position estimation of gripper and carbon nanotube are proposed. On the one hand a depth from focus method using real-time processing of noisy SEM images and on the other hand a touchdown sensor concept based on a bimorph piezo bending actuator. Both methods are described in a theoretical framework and are partly verified by experimental tests.