Role of Oxygen Vacancies in the Electrical Properties of WO_3−x Nano/Microrods with Identical Morphology

Figure 3

Typical SEM images of the samples prepared by thermal evaporation of 1 g WO₃ powder and different amounts of S powders at 1150°C separately: (a) 0.1, (b) 0.15, (c) 0.2, and (d) 0.5 g.

(a)

(b)

(c)

(d)