Deposition refers to the formation of matter on surfaces by depositing it there; this process stands in stark contrast with sublimation, which involves changing gases directly to solid without passing through liquid state first. Examples of deposition include frost and snow.
Deposition is one of the processes that help shape Earth, but it can also have detrimental effects on its ecosystems.
Physical
Physical deposition is a vacuum process for depositing material vapor onto substrates. This form of thin film synthesis has many advantages over chemical deposition methods, including high step coverage/conformality, improved optical properties and lower residual stress levels.
As an example of physical deposition, consider frost or hoar frost formation on leaves in subfreezing air temperatures. This occurs because water vapor loses enough thermal energy for direct conversion from its liquid state into an icy state without first changing to liquid form first.
Physical Vapor Deposition (PVD) involves heating solid material into its gaseous state before depositing it onto a substrate. This technique creates highly crystalline films of high density and quality that can also generate insulating and semi-conducting materials for use in LEDs, solar panels and other electronic devices, decorative protective coatings as well as medical and technological uses.
Chemical
Chemical deposition science involves using chemical substances to transport volatile molecules to surfaces used as substrates. This field encompasses chemical vapor deposition (CVD) and atomic layer deposition processes that are employed for thin-film growth on various substrates. These processes are particularly well suited for applications where a combination of materials must be assembled to perform some useful function, such as creating an electronic chip or altering the surface of a tool with specific morphologies. Chemical deposition techniques differ from physical vapor deposition in that they do not necessitate liquid phase addition, thus eliminating impurities or defects introduced through physical methods of thin film production such as physical vapor deposition. Also see chemical solution deposition and sol-gel processing.
Biological
As part of life sciences, deposition is an essential concept in biological studies. Microorganisms attach themselves to surfaces in a manner similar to particle deposition; when attaching macromolecules however, their attachment resembles more adsorption than particle deposition.
Chemical pollutants like lead, mercury, cadmium and arsenic often settle out into sediments from both natural and industrial processes, where they deposit their toxic substances that have direct and indirect impacts on organisms that consume the affected individuals. Lead’s direct effect includes reduced foraging success in fish while mercury’s indirect effect includes increasing its concentration in birds that consume polluted fish as food sources.
Voucher specimens deposited in recognized, permanent research collections provide the only reliable method for authenticating taxa used in biological, agricultural, ecological and faunistic research. Furthermore, these specimens serve as invaluable resources in the identification of new species, revision of taxonomies and systematization efforts.
Economic
Deposition refers to the process of depositing materials onto surfaces through various means such as wind, ice, water or gravity. Wind and ice may transport previously weathered material that will eventually settle onto landforms as sediment as its energy decreases; gravity can also deposit materials such as minerals or building stones.
Economics of deposition refers to the study of mineral deposits for their potential commercial value. Geologists who specialize in this field are known as economic geologists, and work to find mineral reserves and assess extraction costs.
Students ages 8+ may begin learning deposition in school from Year 4 onwards (aged 8+). Children can explore states and changes of state such as carbon dioxide solidifying without becoming liquid; when looking at frost on windows or rocks. Legal professionals use depositions as out-of-court examinations in which witnesses answer questions from both sides in a case and many cases settle via these means prior to going to trial.