I have seen 'n' of papers talking about deposition of semiconductor shells on metal surfaces. However, there is a very limited literature about the deposition of metal shells on semiconductor nanocrystal. Why is it hard to achieve a full or complete shell on semiconductor?
Please pour your suggestions.
https://www.google.com/url?q=https://www.researchgate.net/publication/23639043_Synthesis_of_Metal-Semiconductor_Core-Shell_Nanoparticles_Using_Electrochemical_Surface-Limited_Reactions&sa=U&ved=2ahUKEwj87au_zYzvAhVj8OAKHTf1CD0QFjAHegQICRAB&usg=AOvVaw0kKJgS5ypry54ksjSoWwRX
Hello,
The great question isn't about the synthetical approach for semiconductor/metal core/shell heterojunction formation, but the objective for this material.
The relative bands position of semiconductor (SC) when compared with Fermi level for metallic (M) coverage determine possible applications.
Generally, it made coverage of semiconductor nanocrystals with SiO2, for example, to decrease the toxicity.
For the development of SC/M heterojunction, the key is the interface to control the growth of SC, and additionally permit the linkage with M. For example the use of two functionalized heads of ligands, that permit the link with interfacial ions of SC and metallic atoms, in another interface. For example di-thiols or conjugated ligands.
The Cadmium(II) is a soft acid of Pearson and can link with soft bases, such as thiols. The Silver is too able to the formation of Ag-S link. And the use of special ligands permits this design.
Hope this helps
Best regards.
Hello Anchal,
the term 'shell' is used in relationship to core/shell nanowires. Your question answers if we discuss the purpose of the shell in such a material combination:
Normally, the shell is used to modulate the properties of the core-nanowire. We want to influence the properties of the core by the shell but (mostly) we don't want that the shell takes part in the transport of electrons or holes. A metallic shell would determine the conductivity of our nanowire.
What effects the shell:
-Due to the strain between core and shell we can influence the gap of the core. (We investigated Bi-nanowires. Pure nanowires are halfmetallic. Due to strain we can convert it to a semiconducting material).
-Due to the band discontinuity between core and shell we can enclose carrier within the core. The formation of a heterojunction can reduce the surface recombination.
-A shell stabilizes the core. If you want to investigate very small nanowires (below ~10nm diameter) the density of states changes remarkably. Such 1-dimensional systems are from high interest but it cannot produced freestanding. Of course you want to profit from such low dimensional system and not from the shell properties. The shell is only the tool to achieve certain properties.
Best regards
R. Mitdank
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