Impact electrical property of alkali metal doped ZnO

Calculate the electronic structure of alkali metal ion-doped Zn crystal, based on density functional theory (DFT) first-principles plane-wave ultra-soft pseudo-potential method. Analyze the band structure of alkali metal ion-doped ZnO crystal, and the electronic density of states. The results indicated that in theory, the doping of alkali metal ions are able to form a p-type ZnO semiconductor, and introduce in the deep acceptor levels. In the actual substitution process, the dopant ions may enter the interstitial site. Thus the alkali metal ions are tending to become donor interstitial impurities. In addition, since the ionic radius of K is larger than the ionic radiuses of Li and Na. And K+ formed the minimum acceptor level (0.078eV), which is a shallow acceptor level. K+ is better than Li+ and Na+ as a dopant. In short, they are not good p-type dopants.