| As a sensing device in nano-scale, scanning probe microscopy (SPM) is a powerful tool for exploring nano world. Nevertheless two fundamental problems tackle the development and application of SPM based imaging and measurement: slow imaging/measurement speed and inaccuracy of motion or position control. Usually, SPM imaging/properties measuring speed is too slow to capture a dynamic observation on sample surface. In addition, Both SPM imaging and properties measurement always experience positioning inaccuracy problems caused by hysteresis and creep of the piezo scanner. This dissertation will try to solve these issues and proposed a SPM based real-time multimodal sensing system which can be used in nano/bio environment. First, a compressive sensing based video rate fast SPM imaging system is shown as an efficient method to dynamically capture the sample surface change with the imaging speed 1.5 frame/s with the scan size of 500 nm * 500 nm. Besides topography imaging, a new additional modal of SPM: vibration mode, will be introduced, and it is developed by us to investigate the subsurface mechanical properties of the elastic sample such as cells and bacteria. A followed up study of enzymatic hydrolysis will demonstrate the ability of in situ observation of single molecule event using video rate SPM. After that we will introduce another modal of this SPM sensing system: accurate electrical properties measurement. In this electrical properties measurement mode, a compressive feedbacks based non-vector space control approach is proposed in order to improve the accuracy of SPM based nanomanipulations. Instead of sensors, the local images are used as both the input and feedback of a non-vector space closed-loop controller. A followed up study will also be introduced to shown the important role of non-vector space control in the study of conductivity distribution of multi-wall carbon nanotubes. At the end of this dissertation, some future work will be also proposed to fulfill the development and validation of this real-time multimodal sensing system. |
