Strain and Heteroepitaxy

This lecture delves into the impact of strain on the band structure of semiconductors, focusing on epitaxy and heteroepitaxy. It covers the accumulation of strain energy due to lattice-mismatch, critical thickness to avoid defects, and the derivation of out-of-plane deformation using Hooke's law. Examples are provided for cubic crystals, highlighting the shift in energy levels near the band gap under different types of strain. The discussion extends to quantum wells, extended defects like dislocations, and experimental setups for exploring strain. Elasticity theory is introduced to understand the relationship between stress, deformations, and elastic constants in cubic crystals.