Wetting layer

In experimental physics, a wetting layer is an initial layer of atoms that is epitaxially grown on a surface upon which self-assembled quantum dots or thin films are created. The atoms composing a wetting layer can be semimetallic elements/compounds (usually InAs in the case of self-assembled quantum dots) or metallic alloys (for thin films). This article refers to the wetting layer used for quantum dot applications. By spraying a surface with layers of these atoms under high temperature, this wetting layer residue is produced on the surface. Wetting layers control the artificial atomic states of the quantum dot for uses in quantum information processing and quantum computation. In experimental physics, a wetting layer is an initial layer of atoms that is epitaxially grown on a surface upon which self-assembled quantum dots or thin films are created. The atoms composing a wetting layer can be semimetallic elements/compounds (usually InAs in the case of self-assembled quantum dots) or metallic alloys (for thin films). This article refers to the wetting layer used for quantum dot applications. By spraying a surface with layers of these atoms under high temperature, this wetting layer residue is produced on the surface. Wetting layers control the artificial atomic states of the quantum dot for uses in quantum information processing and quantum computation. The wetting layer is epitaxially grown on a surface using molecular beam epitaxy (MBE). The temperatures required for wetting layer growth typically range from 400-500 degrees Celsius. When a material A is deposited on a surface of a lattice-mismatched material B, the first atomic layer of material A often adopts the lattice constant of B. This mono-layer of material A is called the wetting layer. When the thickness of layer A increases further, it becomes energetically unfavorable for material A to keep the lattice constant of B. Due to the high strain of layer A, additional atoms group together once a certain critical thickness of layer A is reached. This island formation reduces the elastic energy. Overgrown with material B, the wetting layer forms a quantum well in case material A has a lower bandgap than B. In this case, the formed islands are quantum dots. Further annealing can be used to modify the physical properties of the wetting layer/quantum dot . The wetting layer is a close-to mono-atomic layer with a thickness of typically 0.5 nanometers. The electronic properties of the quantum dot can change as a result of the wetting layer . Also, the strain of the quantum dot can change due to the wetting layer .