Editing Wetting layer (section)

==Process==

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]].<ref>{{Cite journal | last1 = Lee | first1 = S. | last2 = Lazarenkova | first2 = O. | last3 = Von Allmen | first3 = P. | last4 = Oyafuso | first4 = F. | last5 = Klimeck | first5 = G. | title = Effect of wetting layers on the strain and electronic structure of InAs self-assembled quantum dots | doi = 10.1103/PhysRevB.70.125307 | journal = Physical Review B | volume = 70 | issue = 12 | year = 2004 | page = 125307 |arxiv = cond-mat/0405019 |bibcode = 2004PhRvB..70l5307L | s2cid = 13994641 }}</ref> Overgrown with material ''B'', the wetting layer forms a [[quantum well]] in case material ''A'' has a lower [[band gap|bandgap]] than ''B''. In this case, the formed islands are [[quantum dots]]. Further [[Annealing (metallurgy)|annealing]] can be used to modify the physical properties of the wetting layer/[[quantum dot]]<ref name="SanguinettiMano2008">{{cite journal|last1=Sanguinetti|first1=S.|last2=Mano|first2=T.|last3=Gerosa|first3=A.|last4=Somaschini|first4=C.|last5=Bietti|first5=S.|last6=Koguchi|first6=N.|last7=Grilli|first7=E.|last8=Guzzi|first8=M.|last9=Gurioli|first9=M.|last10=Abbarchi|first10=M.|title=Rapid thermal annealing effects on self-assembled quantum dot and quantum ring structures|journal=Journal of Applied Physics|volume=104|issue=11|year=2008|pages=113519–113519–5|issn=0021-8979|doi=10.1063/1.3039802|bibcode=2008JAP...104k3519S |doi-access=free}}</ref>
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