Is surface doping like attachment of noble or other metals at the exterior of nanomaterials? Hetrojunctions are developed in the second case, but dopant is in very small concentration ,would it also develop hetrojunction? and in the same way?
Hello, in general, I found ,the n-type of semiconductors are formed schotky barrier when doped by metals, but the p-type semiconductors are formed ohomic barrier when doped by metals..... if two semiconductors N and P-types composite and doped one or two metals on surfaces them, Now, this effect needed to wide study and formed hetrojunction.
In case of gas sensing materials we found that there is an electronic interaction between oxidized Pt clusters and tin dioxide. This effect was observed for a loading of 0.08 wt% Pt (see DOI: 10.1039/C7TA08781K ). However, you should keep in mind that the structural effects play role, e.g. oxidation sate of the loading or whether it forms a separate phase or not.
I hope this input from gas sensor research is useful for your work.
WO3 always loaded with noble metals such as Pt and Pd. We found the resistance is greatly increased due to the hetero-junction. I think you may consider the properties of support.
There will be maximum possibility of the development of heterojunction as any dopant will definitely perturb the electronic properties of the material.