The value of 1 monolayer (ML) is not a universal constant; it varies based on the material and crystal structure being deposited. For example, in the case of InAs quantum dots, a height of "5nm-height 2.5ML" indicates that the structure consists of two complete layers and one half-filled layer, with the exact thickness influenced by factors such as surface termination. The use of monolayers simplifies the measurement process during film growth, particularly when utilizing techniques like Reflection High-Energy Electron Diffraction (RHEED) oscillations.
PREREQUISITESResearchers in material science, physicists studying quantum dots, and engineers involved in thin-film deposition techniques will benefit from this discussion.
yzou_ua said:Always be used in experiments... but when it appears in literature, most authors never tell the exact value of 1 ML (monolayer).
So, what is the value, generally??
ZapperZ said:This is not a universal value. It depends on the material and crystal structure of what is being deposited.
Zz.
yzou_ua said:So w/o telling from author, we can never know it??
ZapperZ said:Unless you know the crystal structure. If the author usually doesn't say, then it's a "common" material that he/she would assume that everyone knows already. This is often the case for, say, high-Tc superconductors or well-known compounds such as Al2O3 or TiN.
Zz.
f95toli said:2 monolayers will probably be of that order of magnitude, yes. But the exact value will depend on e.g. the termination of the surface etc.
Also, 2.5ML would mean 2 complette layers and one half-filled layer; meaning the top-most layer does not cover the whole surface. Again, what it looks really like will depend on the materials etc.
Btw, the reason the thickness is given in monolayers is because it is much easier to "count" the number of layers (using RHEED oscillations) during the film growth than it is to actually measure the thickness of the film.