Bravais Lattices: The Foundation of Semiconductors

Before we can stretch bonds in a complex alloy, we must understand how the atoms pack together. In Class 11, we learn about the three fundamental cubic structures.

1. Simple Cubic (SC)

The most basic, but least efficient packing. Atoms sit strictly at the 8 corners.

2. Body-Centered Cubic (BCC)

Here, a single atom sits directly in the center of the unit cell at $(0.5, 0.5, 0.5)$.

3. Face-Centered Cubic (FCC)

This is the parent structure of almost all semiconductors. It features atoms on the 8 corners and exactly in the center of the 6 faces.

Notice how as you rotate the FCC crystal, the "Face" atoms align perfectly to block your view through the center? That is the essence of close-packing.