Semiconductors’ emergence totally revolutionize information technology, medical field, defense and security, electronics and what not. Various approaches, e.g. heteroepitaxy of semiconductors, have been adapted to meet demands in microelectromechanical (MEMS) and nanoelectromechanical (NEMS) technology. Use of heteroepitaxy is limited due to lattice matching constraint between substrate and overgrowth layer. Mechanical strain engineering is also an emerging method to modulate semiconductor properties to meet desired applications. A biaxial tensile strain of nearly 2% in Germanium make it a direct bandgap semiconductor from indirect one via lifting degeneracy of energy bands. This motivates us to observe effect of strain on Silicon’s band structure, most abundant semiconductor and explore its use for photonic applications. Lateral structure of Silicon nanomembrane has been grown over flexible polyimide sheets and the fact that various thicknesses of Silicon nanomembrane contain different strain energy under applied mechanical stress has been used to map Raman spectrum over these nanomembrane structure. This helps in understanding strain effect via simple Raman spectro-microscopy. Figure 1a shows geometrical structure of varied thickness of Silicon nanomembrane and corresponding change in Raman peak poistions is observed clearly from Figure 1b.

Tracking lateral strain inhomogeneity in varied thicknesses of single silicon nanomembrane

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.