Figure 2.

Calculated total valence charge density plots of a clean Si substrate, b isolated H atoms, c9H-Si(111)-7 × 7 and d the difference charge density plot by subtracting Fig. 2a and 2b from 2c. The area is 11.5 × 8 Å; the contours interval is 0.1e Å−3 for Fig. 2a, 2b and 2c and 0.5e Å−3 for Fig. 2d. Positive contours are shown as solid lines, negative contours as dashed lines and zero contours have been omitted. A is for Si adatom and R for Si rest atom, respectively

Lin et al. Nanoscale Research Letters 2009 5:143-148   doi:10.1007/s11671-009-9456-x