Characterizing electrically active defects by transient capacitance spectroscopy

In this chapter, characterization of electrically active defects is discussed and transient capacitance measurement techniques are addressed. The chapter starts by introducing the main properties describing the electrical activity of a defect, before techniques to measure these properties using thermal and optical emission are discussed. Key techniques based on measuring capacitance transients are reviewed, with particular emphasis on DLTS, including how DLTS can be utilized for direct measurements of capture cross sections and defect profiles. The latter part of the chapter shows examples of use, where defect studies in silicon is chosen as a well established material where most of the defect levels are identified, but where fundamental knowledge of the defects can still be gained. Defects in zinc oxide (ZnO) is also discussed and chosen as a less studied material where direct identification of the origin of the defect levels remains an important challenge.