Breaking the absorption limit of silicon toward the short-wavelength infrared wavelength range via strain engineering
Silicon is widely used in the microelectronics industry although its photonics applications are restricted to the visible and partial near-infrared spectral range due to its fundamental optical bandgap. Researchers have therefore used recent advances in strain engineering to tailor material properties, including the optical bandgap. In a recent study now published on Science Advances, Ajit K. Katiyar and a group of scientists in electronic engineering and materials science in the Republic of Korea, reported strain-induced shrinkage in the silicon (Si) bandgap. The process facilitated photosensing beyond the fundamental limit within silicon nanomembrane photodetectors (abbreviated Si-NM PD). The team mechanically stretched the Si-NM PD pixels using a maximum strain of 3.5% to enhance photoresponsivity and extended the silicon absorption limit up to 1550 nm with applications suited for lidar sensors and obstacle detection during self-driving. They then developed a deformable three-dimensional (3-D) optoelectronics framework with concave and convex hemispherical architectures for...