Electrical conductivity and doping

Abstract

In this chapter, the electrical properties of ZnO are discussed, which essentially include doping, carrier mobility, contacts, and some other topics listed below. Nominally undoped ZnO is always n-type. This fact could be possibly due to intrinsic defects or due to hydrogen, which is a donor in ZnO and a rather ubiquitous element (also in most of the growth processes). Therefore, hydrogen in ZnO is treated first and then other donors for efficient n-type doping. The next section is devoted to p-type doping and the persistent difficulties to obtain reliable, stable, and high p-type conductivity. The chapter continues with information on the carrier mobility and the observation of the integer quantum Hall effect. The next electric properties concern the use of ZnO in varistors and high-field transport. The final aspect is photoconductivity.