Zinc oxide(ZnO)film has been interested by more and more researchers

because of its wide handgap(3.3 eV)and strong exciton binding energy(60 meV).These properties make ZnO have some potential applications in photonics area

such as UV photo-detectors and emitting diodes.In order to fabricate optoelectronic devices

two problems should be resolved.One is the epitaxy of ZnO crystal film

and another one is the p-type doping.This paper mentions the possible methods for epitaxy of ZnO crystal film and p-type doping.We have used Zn buffer layer to improve the quality of ZnO film deposited on Si substrate

according to multi-lattice marched principle.Moreover

we proposed to use SiC buffer layer for depositing ZnO film on Si substrate

because of many advantages possessed by SiC.For p-type doping of ZnO film

there are some difficulties:(a)p-type doping will raise Madelung energy;(b)self-compensation effect prevents national n-type ZnO return to p-type;(c)acceptors have insufficient activation in ZnO films by using p-type impurity alone.The codoping method using group V elements and group Ⅲ elements as codopants may be favorable to solve these difficult

example using N:Ga=2:1.It could increase the incorporation of the acceptors due to the strong attractive interactions between the acceptor and donor dopants.It also could lower the energy levels of the acceptors and raising those of the donors in the bandgap.Then the acceptors can be ionizable easier.