SEM images of a p-type Ge(100) surface loaded with metallic particles. (a) After deposition of Ag particles (φ 20 nm). (b) After immersion in water for 24 h. (c) After immersion in water for 72 h. Crystallographic directions are given for this figure, indicating that the edges of the pits run along the <110> direction. (d) After deposition of Pt particles (φ 7 nm). (e) After immersion into water for 24 h. Square pits, probably representing inverted pyramids, are formed as well as some pits with irregular shapes such as ‘rhombus’ and ‘rectangle’. In (a) and (d), some particles are indicated by white arrows. In (b), (c), and (e), the samples were immersed in saturated dissolved-oxygen water in the dark.