Another way to see what the (111) crystal planes in diamond lattice look like is to use "cork-ball" models shown below. The left image below shows a top view of the atomic arrangement for the (111) plane. The right image shows a 3-dimensional view of the same surface. In both cases atoms are color-coded: orange for the top layer and green for all the deeper layers. These images have been generated with the help of the Surface Explorer web-based tool. You can use it to visualize many other surfaces as well.

When (111) surface of Silicon is heated to sufficiently high temperature under the Ultra-High Vacuum conditions the surface atoms rearrange for a more energetically stable configuration called 7x7 reconstruction. Instead of a very simple pattern shown above, the new arrangement involves several types of atomic positions in the top three atomic layers to form a much larger unit cell. A schematic of this new unit cell is shown below on the left with color-coding referring to different types of Silicon atoms. The new unit cell is outlined. Below on the right is an STM image of Si(111) surface with several unit cells shown. The "corner-holes" correspond to the corners of the unit cell and the atoms imaged as bright protrusions correspond to the atoms highlighted in orange in the schematic view.

Below is a 3D representation of the 7x7 STM image shown above. For a semiconductor such as Silicon this picture is in fact quite close to the actual atomic arrangement on the surface. The image is 18x8 nm², and the height of the "bumps" is only about 0.04 nm - a fraction of atomic size.

Stepped Silicon Surfaces
Main Nanowiz Page

Univ of MD site with stepped Si(111) info
Make surface models with Surface Explorer