Progress in ZnO Acceptor Doping: What Is the Best Strategy?

Figure 5

Raman spectra of a N-doped ZnO film show that excess H⁺ bound to the O_𝑖^−1(oct) and Zn_𝑖^−1(oct) present after the in situ anneal (black) is removed from the film after the ex situ 800°C O₂ anneal (red).