Introduction to Nanoscience and Nanotechnology

Chapter 5

Single-Nanoparticles Devices

The focus so far has been on the special properties of nanostructures, or advanced materials formed from them, which is broadly covered by the term incremental nanotechnology defined in the introduction. In this chapter we will examine the possibility of making nano-devices built out of a single nanostructure. This can be, for example, a metal or semiconductor nanoparticle, a fullerene molecule, or a carbon nanotube “functionalized” to individually perform a task. The chapter thus delves into the world of evolutionary nanotechnology. Some examples of the kind of system we will be dealing with were briefly described in the introduction (see Fig. 0.3). The emphasis will be on electronic devices or data storage rather than on nano-mechanical systems, though there are some splendid examples of these based on individual nanostructures—for example, the nano-cheesewire described in Chapter 3 (see Fig. 3.20). The focus will be on three examples of functionalized particles—that is, magnetic nanoparticles for storing digital data, nanoparticles that act as electronic components for ultra-high density circuits, and light-emitting quantum dots. There are many additional examples, but the topics presented here will provide an understanding of what is meant by Evolutionary Nanotechnology. The nanoparticles discussed in this chapter can also be functionalized with biological molecules to perform a medical function, but the discussion of these is deferred ...