Semiconductor Materials

Group of materials having conductivities between those of metals and insulators

• GaAs is a more common semiconductor compound
• Optical properties make it useful in optical devices, and high-speed mediums

Types of Solids

Type of solid characterized by size of ordered region within the material

Amorphous, polycrystalline, and single crystals

Amorphous

• Have order only within a few atomic or molecular dimensions

Polycrystalline

• Have a high degree of order over many atomic or molecular dimensions

Single

• Called grains and are separated by grain boundaries
• High degree of order throughout the entire volume of the material

Space Lattices

A representative unit, or group of atoms, repeated at regular intervals in each of the three dimensions to form the single crystal

• The periodic arrangement of atoms in the crystal is called the lattice

Primitive and Unit Cell

• A lattice point is a way to represent a particular atomic array

• Each lattice point can be translated a distance $a_1$ in one direction and distance $b_1$ in another direction to generate the 2D lattice

  

  2D representation of a single-crystal lattice