TABLE OF CONTENTS Magdalena Lidia Ciurea,
National Institute of Materials Physics,
Bucharest,Romania e-mail: ciurea@infim.ro
Abstract In this chapter, trapping phenomena in nanocrystalline semiconductors (materials and devices) are presented and analyzed. The small number of atoms in a nanocrystalline semiconductor makes the contributions of the traps to different phenomena much more important as compared to a bulk semiconductor. The conventional (experimental) methods most frequently used for the investigation of traps are described. I also discuss which methods are suitable to be used for the trap investigation in nanocrystalline semiconductors and what are the trap parameters that can thus be obtained. The application of these methods, together with different non-conventional methods, to the study of the traps in nanocrystalline semiconductors, is presented. The role of the traps in possible applications as well as functioning problems of different devices is outlined.
It is important to study the trapping phenomena in semiconductor materials and devices because these phenomena contribute to different properties of the materials and can modify some parameters of the devices. In nanocrystalline semiconductors, the traps play an even more important role. Indeed, a single trap in a nanocrystal of 1000 atoms represents a trap concentration much greater than any value attained in bulk semiconductors.
In the following, the definitions of a trap center and of the related parameters are presented. The differences between trapping and recombination centers are discussed. Next, the particularities of the traps in nanocrystalline semiconductors are described, together with the special phenomena that take place...
