StrainEngineering

StrainEngineering, often referred to as strain engineering, is the deliberate introduction and control of mechanical strain within a material or structure to modify its properties. It spans fields such as semiconductor physics, materials science, energy materials, photonics, and mechanobiology, and can involve tensile, compressive, or shear strains applied statically or dynamically.

In electronics, strain engineering is used to enhance device performance by altering carrier mobility and band structure. In silicon CMOS, lattice-mismatch or epitaxial layers of SiGe or related alloys create tensile strain that increases electron and hole mobilities. Strain also tunes band gaps and optical transitions in various thin films and heterostructures, enabling improved transistors, lasers, and LEDs.

Methods include epitaxial growth with lattice mismatch, patterned or flexible substrates, thermal expansion mismatch, and external actuation such as bending, stretching, or mechanical indentation. Strain can be uniform or gradient and is characterized by techniques such as X-ray diffraction, Raman spectroscopy, and electron microscopy.

In materials science and energy research, strain engineering tunes properties of perovskites, oxide interfaces, and two-dimensional materials, affecting conductivity, ferroelectric behavior, catalytic activity, and energy storage performance.

In biology and tissue engineering, mechanical strain can influence cell fate and tissue development. Microfluidic devices and stretchable scaffolds apply controlled strains to guide differentiation, alignment, and function through mechanotransduction.

Challenges include achieving spatially uniform strain at device scales, managing fatigue and degradation, and integrating strain-engineered components into scalable manufacturing processes. The approach is part of a broader strategy to tailor material properties with minimal chemical changes.