Fig. 7
Proposed model of the O a, O b, and O c distribution, Φ and band bending diagrams of ZnO NRs after treated by hydrogen for 2 h, a ZnO NR chemical composition without H2O, b band bending ZnO NRs without H2O, c ZnO NR chemical composition with H2O, and d band bending ZnO NRs with H2O. Note that Φ value variations from bulk to surface shown in a and c are not subjected to Gutmann et al. [19] 0.3–0.35 eV correction factor