How to calculate the lattice mismatch between two semiconductor compounds (especially in solar cells)? Further, how to come to a conclusion regarding the probability of a successful fabrication of the two layers?
Lattice mismatch between the two materials composing the active junction may have serious effect on the electrical performance of solar cells by introducing traps for the charges and recombination centers that cause losses of excess charges. This type of junctions are called hetero junctions and they are studied intensively in the literature. One remedy of the lattice mismatch is to passivate the interface states by oxidation or hydrogenation. The other main technique is the intermixing of the two materials at the interface to form an intermediate layer.
In case of epitaxial structures where the two stacked materials must be lattice matched or the lattice mismatch is so small that can be absorbed in few layers at the interface, one can not allow more that upper bound for the mismatch. For heterojunctions one can allow far more difference between the lattices.You need only to think in organic solar cells which are not formed from crystalline materials but from very fine grained to amorphous materials.
Lattice mismatch between the two materials composing the active junction may have serious effect on the electrical performance of solar cells by introducing traps for the charges and recombination centers that cause losses of excess charges. This type of junctions are called hetero junctions and they are studied intensively in the literature. One remedy of the lattice mismatch is to passivate the interface states by oxidation or hydrogenation. The other main technique is the intermixing of the two materials at the interface to form an intermediate layer.
In case of epitaxial structures where the two stacked materials must be lattice matched or the lattice mismatch is so small that can be absorbed in few layers at the interface, one can not allow more that upper bound for the mismatch. For heterojunctions one can allow far more difference between the lattices.You need only to think in organic solar cells which are not formed from crystalline materials but from very fine grained to amorphous materials.
Buffer (soft) layers can be used to overcome the lattice mismatch. Such may be, for example, porous layers.
I would like that you see an example of the heterojunction of 2-6 compound solar cells by following the papers where they introduce a complete study of such solar cells. The effect of interface is investigated in details: Article Capacitance and conductance of ZnxCd1-xS/ZnTe heterojunctions
and the paper: Article M. Abdelnaby, A. Zekry, F. Elakkad and H. F. Ragaie, “ Depen...
Best wishes
Lattice mismatch, thermal expansion coefficient effect ( in case of high temperature grown layer) and type of unit cell all are considerable parameters for successful HJ device fabrication. Iso-electronic materials with well physical symmetry is expected for better HJ
Thank you Bablu K. Ghosh Abdelhalim Zekry Yana Suchikova for your answers. They were very helpful.
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