Hi Sukriti,

Heterostructures are the materials made up of different metals or components. They are not separate species. You will get only one morphology where they are completely blended with each other. They are interlinked. Ex. MnMoO4, CuWO4

Composites are the materials where 2 or more components present independently with given ratio. They will have individual identity and can be observed through SEM and TEM. Ex. Cu2S-MoO3.

In terms of band gap, for heterostructures usually get only one band gap energy (sometimes 2) but composites get minimum of 2 band gap energies.

Core-shell structures are those where one component is enveloped by other. These may be considered as a type of composites. Of coarse band gap energy will not be same as that of either of the components. It depends on the composition ratio.

Hope it helps

Hi Sukriti,

Heterostructures are the materials made up of different metals or components. They are not separate species. You will get only one morphology where they are completely blended with each other. They are interlinked. Ex. MnMoO4, CuWO4

Composites are the materials where 2 or more components present independently with given ratio. They will have individual identity and can be observed through SEM and TEM. Ex. Cu2S-MoO3.

In terms of band gap, for heterostructures usually get only one band gap energy (sometimes 2) but composites get minimum of 2 band gap energies.

Core-shell structures are those where one component is enveloped by other. These may be considered as a type of composites. Of coarse band gap energy will not be same as that of either of the components. It depends on the composition ratio.

Hope it helps

Thank you so much Shivaraj Sir. It really helped a lot.

Then, what are heterostructure composites? How do we differentiate between core-shell type or contact type heterostructures?

Dear Sukriti Khera, you need to accept that these terms are not strictly divided.

composite, as the term suggests, is composed from 2 or more components, they can be simple mixture, core shell, two layers of 2D layers, liquid in foam, etc, each of these individual materials (from which the composite is composed) may or may not have band-gap, overall composite depending on its structure may have(or not) leveraged band-gap, that depends on point of view. if you consider exciton, then maybe you focus on one component, and then exciton may migrate to second component that has different band gap, and for different situation you should consider the second band gap.

heterostructure is also generalized term for compost.

one more thing must be noted that heterostructure or composite can be made of the "same chemical compound" in different structure.

Thank you Artavazd Sir for your answer.

Dear Sukriti,

agreeing with Dr. Artavazd.

I think Fig.1 of following article may help you understand/imagine the difference between composite and coreshell microstructure (atleast).

DOI:10.1016/j.jallcom.2016.01.170Article Gradient Core-shell microstructure in mixed valence multifer...

In addition to Shivaraj´s answer the term heterostructure will be used in semiconductors to describe the junction between two different materials often with different bandgaps e.g. in LED´s solar cells or lasers. The main concern here is the band alignment of valence and conduction bands at the interface or the existence of reacted Interfaces with new electronic properties . In core-shell structure we have the problem of nano structures where the bandgap may be different from the bulk material and the junction is more complicated as we have often not a well defined interface as crystallographic planes are not well develloped, causing new interface states to appear in the elctronic properties of the junction. An example for a bilayer system is the Schottky contact of a semiconductor and a metal, again the junction properties are of enterst which detrmine the barrier height.

Thanks Christian Pettenkofer Sir.