Ion implantation and low-temperature diffusion steps for solar cells
The objective of the research is to make ion implantation become the leading technology for next future of c-Si solar cells. In order to achieve this task, fundamental study is being carried out, starting from the physics of the ion implantation and from preparing, testing and characterizing the so called “Half-fabricate” cells, like that one shown in the figure below:
From this structure, we can understand all the important properties that a solar cell should include:
- Implantation recipe (Ion species (B,BF2,P,Sb,As) energy, dose, annealing temperature and time)
- Passivation (chemical and field effect) to measure the recombination of a layer (Emitter or BSF)
- Anti-Reflection coating on a textured substrate
- Contact resistance (It gives information on FF)
One of the objective of my research is to build up a so-called ADEM solar cell, that consists in a bi-facial solar cell that can convert the energy from the front and from the back side. Optimization of this device is needed using poly-silicon to achieve high VOC in a so-called PolyADEM solar cell. Of course, the full-implantation approach can be used in other architecture like Interdigitated Back Contacts (IBC), leaving some new challenges to achieve high VOC and FF.