# Seminar: Semiconductors
Topics for Winter Term 04/05

| Team | Assistant General: Dr. Riemenschneider | Date
We Will Focus on Solar Cells
Topics
| Markets, Technologies, Companies - an Overview |  |  |
| Solar Energy - what we get, we can use. |  |  |
| Humans and Energy: Where it comes from, how much we use, where we are headed. |  |  |
| Prices of Energy |  |  |
| Solar Cells - History, where it is headed |  |  |
| Basic Principles of Solar Cells and Solar Cell Moduls |  |  |
|  | Basics: IV, efficiency , fill factor, etc.. Essential material parameters (doping, life time, absorption,...). Add series resistance, add parallel resistance; discuss. Temperature dependence of efficiency etc. |  |  |
|  | Equivalent circuits, local variations of parameter. |  |  |
|  | Making Moduls. Problem of series resistance, shadowing |  |  |
| Crystaline Silicon Solar Cells |  |  |
|  | Monocrystalline high-efficiency cells. Mass product vs. world record winners. n- vs. p-doping. |  |  |
|  | Polycrystalline Cells. Making poly, making cells. Si shortage problem |  |  |
|  | Sliver Cells and other specialities. |  |  |
| The CIS Family |  |  |
|  | CuInSe2and related materials. What makes them special? |  |  |
|  | Give properties of materials and specifics of technology; Sputtering vs. CVD? |  |  |
|  | Specifics of technology: Series connection, stability, ... |  |  |
|  | Discuss the role of crystal lattice defects and of hydrogen passivation2 |  |  |
|  | Discuss related materials, pro and cons, e.g. HgCdTe systems |  |  |
| Amorphous and Nanocrystalline Thin-Film Si Solar Cells |  |  |
|  | Discuss amorphous Si cells. What went wrong? |  |  |
|  | New developments. "Thin" and "Thick" Thin-Film cells. |  |  |
|  | Potential and specifics |  |  |
| Tandem Cell, "Nano Cells and Exotica |  |  |
|  | Discuss tandem principle |  |  |
|  | Examples for tandem cell development |  |  |
|  | State of the art, potential for future |  |  |
|  | New concepts with e.g. nanodots |  |  |
| Characterization Techniques |  |  |
|  | Characterizing a finished solar cell. Doing it with local information. Doing it in 1 s. |  |  |
|  | Characterizing materials (e.g. poly Si wafers or CIS layers). Which parameters are important? How to measure? How to predict the quality of cells made with the material? |  |  |
|  | Characterizing modules. Give some specific problems. |  |  |

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