Bottom-up fabrication is a process of building structures or materials from individual atoms or molecules, as opposed to top-down fabrication, which involves removing or etching away material from a larger bulk material. The term “bottom-up” refers to the fact that the material is built up from smaller building blocks, starting from the “bottom” level.
Bottom-up fabrication techniques typically involve self-assembly or self-organization of the building blocks, which can be atoms, molecules, nanoparticles, or other small entities. These building blocks interact with each other to form larger structures or materials with specific properties.
Examples of bottom-up fabrication techniques include molecular self-assembly, where molecules spontaneously arrange themselves into ordered structures; colloidal self-assembly, where nanoparticles are used to build up larger structures through interactions with each other; and atomic layer deposition, where atomic layers are deposited one by one to build up a thin film.
Bottom-up fabrication techniques are often used in nanotechnology, Learning Management System and materials science, where precise control over the structure and properties of materials is important. By building materials from the bottom up, it is possible to create structures with novel properties that cannot be achieved through top-down approaches.