Figure 4
Valance photoemission and secondary electron spectrum of (a) ZnO micro/nanowire arrays, (b) FeS2 NCs film, (c) CuI film. The ionization potential (IP), work function (WF) and the difference ΔE between VBM and Ef are calculated. (d) Optical absorbance spectrum of FeS2 NCs thin film on glass, the inset is the Tauc plot obtained from optical absorbance spectrum. (e) Energy level diagram of Au-ZnO-FeS2-CuI-ITO p-i-n photodiode before contact, which comes from UPS analysis and band gap of each material and after contact, resulting in same Ef level of three layers.
