Deposition occurs when erosion agents run out of energy to carry their load of material further, forcing it to settle into new places as deposition takes its place.
Water vapour in subfreezing air can convert directly to crystal frost on windows without first condensing into liquid form, creating an instance of deposition.
Physical
Thin film deposition techniques have played an instrumental role in the growth of various industries over the last century. They include semiconductor electronics, magnetic recording media, integrated circuits and LEDs as well as hard coatings for tools, optical applications and pharmaceuticals. Physical vapor deposition (PVD) is one of the most commonly employed techniques here and involves directly depositing material from its physical source onto substrate in low pressure environments; other well-known methods include sputtering, thermal evaporation carbon coating and electron beam evaporation.
Thin films can be studied using techniques such as X-ray diffraction and Raman spectroscopy, with field emission scanning electron microscopy, transmission electron microscopy and atomic force microscopy being common methods to assess their crystalline structures and microstructure. They can also be analyzed for surface chemistry investigations such as using field emission scanning electron microscopy.
Chemical
Chemical deposition science is an extremely vital aspect of developing advanced electronic devices. Two prominent techniques in this area are Chemical Vapor Deposition (CVD) and Atomic Layer Deposition (ALD), which use volatile molecules transported via gas phase to deposit desired materials onto surfaces via nucleation sites on substrates, serving as nucleation sites for new solid material formation. A second group known as Chemical Solution Deposition or Sol-Gel Processing utilizes liquid phase as mass transfer medium; these techniques produce thin nanostructured blend films of inorganic materials.
Biological
Biomaterials of biological origin exhibit an extraordinary array of structural properties at both micro and nano scales1. Reproducing them accurately to develop functional materials with multiple uses is key.
Particle deposition refers to the spontaneous attachment of particles to surfaces in various natural environments, and most often manifests itself in microscopic form such as pollen grains or sand grains; however, macromolecules like proteins and platelets can also become attached.
An example of particle deposition would be the purple iodine crystals that form when iodine vapor is introduced into the air, creating direct deposition processes in which molecules transition directly from gaseous state to solid form, bypassing liquid state altogether. This process works similarly with physical vapor deposition used for industrial coating applications.
Environmental
A sedimentary depositional environment refers to the conditions under which specific types of sediment accumulates in geologic time. There is a wide array of depositional environments represented throughout Earth history. Wind, ice, water, gravity and other forces transport weathered surface material to sites where its kinetic energy can be converted into sedimentary deposits that build up over time, creating layers of rock or soil formation or other types of sedimentary deposits. Sometimes the juxtaposition of permeable and impermeable rocks can form stratigraphic traps. Examples include eolian sand dunes encased by lacustrine mudstones, fluvial channel deposits covered with marine shales, shallow marine bar sandstones isolated by marls, or carbonate reefs trapped in pelagic mud.