Generation of Stable Photovoltage in Nonstoichiometric CuBi₂O₄ Thin-Film Photocathodes

Figure 2

Topographic surface and cross-sectional SEM images of CuBi₂O₄ thin films under controlled oxygen partial pressures of (a, d) 600, (b, e) 200, and (c, f) 60 mTorr. (g) Raman spectra and (h) estimated cation ratio of the CuBi₂O₄ thin films (thickness ~800 nm) depending on their oxygen partial pressures. Note that the dashed line indicates the cation ratio () of the stoichiometric CuBi₂O₄.

(a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)