semiconductor physics and Devices

Week 1: Crystal Structure (Part 1)

Lecture Topics:

1. Introduction to Solid State Physics

   • Overview of the course and objectives.

   • Introduction to the importance of solid-state physics in modern technology (e.g., semiconductors, materials science, nanotechnology).

2. Basic Concepts of Crystal Structure

   • Solids can be classified as crystalline or amorphous.

   • Crystals are characterized by a periodic arrangement of atoms.

   • Definition of a lattice: A regular array of points in space.

   • Definition of a basis: A group of atoms associated with each lattice point.

   • The combination of the lattice and basis forms the crystal structure.

3. Lattices and Unit Cells

   • Unit cell: The smallest repeating unit that, when translated, reproduces the entire crystal.

   • Types of unit cells: Simple cubic (SC), body-centered cubic (BCC), face-centered cubic (FCC).

   • Parameters defining a unit cell: Lattice parameters (a, b, c) and angles (α, β, γ).

   • Primitive unit cell: The smallest unit cell that can reproduce the entire crystal by translation.

4. Bravais Lattices

   • Introduction to Bravais lattices: There are 14 distinct 3D Bravais lattices, which are the building blocks of all crystal structures.

   • Examples of Bravais lattices: Cubic, tetragonal, orthorhombic, hexagonal, etc.

   • Symmetry properties of Bravais lattices.

Homework/Exercises:

1. Define a crystal, lattice, basis, and unit cell. Explain how they are related.

2. Calculate the volume of a unit cell for a simple cubic lattice with a given lattice constant.

3. Describe the differences between SC, BCC, and FCC lattices and provide real-world examples of materials that exhibit these structures.

Suggested Reading:

• Charles Kittel, Introduction to Solid State Physics, Chapter 1: Crystal Structure.

Key Takeaways:

• Crystals are characterized by a periodic arrangement of atoms, defined by the lattice and basis.

• The concept of the unit cell is central to understanding crystal structures.

• There are 14 Bravais lattices that classify different possible crystal symmetries.

This foundational week provides students with the language and basic concepts needed to study more advanced topics in solid state physics.