In a p-n heterojunction under internal electric field, the photogenerated electrons and holes will transfer to the n-type semiconductor and the p-type one, respectively. It can be assigned to the fact that CB and VB of n-type semiconductor are normally lower than those of p-type semiconductor. It seems that the type-II heterostructure is similar to this p-n photocatalyst. So what is the main difference between these two heterostructures?
In the right side p-n junction structure the field region in the transition region will direct the electrons to the n-side where they will be accumulate on the surface of the n-side. At the same time the photognerated holes will be directed to the p-side where they will accumulate on the surface of the p-type material. So, the p-side will be source of holes which is oxidizing. The electrons accumulating on the n-side will be reducing.
The structure in the the right side is composed of two intrinsic materials with the left side has an electron affinity greater than the right side. The two materials have almost an equal energy gap. Both materials are optically active where on absorbing photons they will both generate electron hole pairs.
The electrons will be accumulated on the left side while the holes will be accumulated in the right side.
So, the right side will be oxidizing while the left side will be reducing.
Both will have photovoltaic effect.
The second structure is simpler to produce than the first p-n junction structure.
Best wishes
Your question is not so clear. p-n junction may be homojunction (say p type Si and n type Si ) or heterojunction (PbS and CdS solar cell). It may also be type I and type II. So type II heterjunction is basically a special class.
Go through any basic book of semiconductor physics.
Dear Milad,
p-n heterojunctions may be of type I or Type II (there is even a Type III that is a special case of type II HJ). Therefore, there is no point in comparing the behaviour of a GENERIC p-n HJ with just one of its SUBCLASSES. Better comparing a type I p-n HJ with a type II p-n HJ (eg GaAs/AlGaAs vs InP/InSb HJs).
Images From
Nanowire Electronics: From Nanoscale to Macroscale.
Jia C, Lin Z, Huang Y, Duan X, Chemical Reviews, 30 Jul 2019, 119(15):9074-9135 DOI: 10.1021/acs.chemrev.9b00164
http://image.slidesharecdn.com/heterojunctionsiliconbasedsolarcells-141107082656-conversion-gate02/95/heterojunction-silicon-based-solar-cells-16-638.jpg?cb=1415348843
https://www.researchgate.net/deref/http%3A%2F%2Fimage.slidesharecdn.com%2Fheterojunctionsiliconbasedsolarcells-141107082656-conversion-gate02%2F95%2Fheterojunction-silicon-based-solar-cells-16-638.jpg%3Fcb%3D1415348843
https://www.researchgate.net/deref/http%3A%2F%2Fimage.slidesharecdn.com%2Fheterojunctionsiliconbasedsolarcells-141107082656-conversion-gate02%2F95%2Fheterojunction-silicon-based-solar-cells-16-638.jpg%3Fcb%3D1415348843
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