Sharif Digital Repository

Metallic clusters are among the best candidates that may be utilized as building blocks for constructing nanostructures. Despite their great potential, a variety of questions arises about their suitability as building blocks at the nanoscale level. One of the key factors in the assembly of nanoclusters is the precise positioning that is required by a manipulation system. The response of clusters, which are subjected to this process, is of great importance. Currently, the size of clusters used as building blocks is shrinking down to a few nanometers. In such cases, the particle nature of matter plays an important role in manipulator/cluster/substrate interactions. Having a deeper insight into... 

Nanopositioning systems are devices with the ability of moving objects within nanometer resolution. In the recent years according to the advancements in the nanotechnology fields, there is an urgent and growing need for these systems as precision motion drivers. In the most of the nanopositiong devices some active materials such as piezoelectric elements are widely used as actuators. Piezoelectric materials can generate a mechanical deformation proportional to the applied electrical field. Therefore, theoretically these devices have the ability to set the desired position with the infinite precision.Design, optimization and fabrication of an ultrasonic piezoelectric motor are performed in... 

Nanopositioning is technology of positioning & manipulation of Nano-scale object. This technology can be considered as one of the fundamental necessities in Nano & Micro research and fabrication and made lots of unbelievable advancement in researches and technologies. There are lots of mechanical systems designed for large scale positioning with sub millimeter resolution, but when it’s come to Nano scale, the range of access should be limited to some micrometer. Also in Nano-scale motion some difficulties like backlash, stick-slip and friction is phenomenon. For increasing the workspace using coarse and fine positioning systems may be an appropriate method. In this method a fine positioning... 

The fabrication of future electronic and optical devices will require advanced nanofabrication techniques that realize high spatial resolution and high precision in controlling size and position, and that are applicable to various materials. Near-field CVD (NF-CVD) was proposed to solve these problems with no need to perform nanolithography prcesses. NFCVD system has two major subsystems, first vacuum chamber and gas distribution system for delivering parent gases to the chamber and second, a nanopositiong system to keep the probe and the sample in the constant systems.In this dissertation we have set up a piezoelectric nanopositiong system and its driver modules. The positioning accuracy...