|Module label||Photovoltaic Cell Technology|
|Credit points||10.0 KP|
|Institute directory||Institute of Physics|
|Applicability of the module||
|Skills to be acquired in this module||
After completing the module, the student will - have a critical understanding of the physical principles relating to the operation and design of photovoltaic cells. - be able to compare and analyse the design and operation of the main types of photovoltaic cells. - have a critical understanding of the effect of material purity and crystallinity on the device performance. - be able to compare and evaluate different methods for the fabrication of photovoltaic cells in terms of device properties and manufacturing issues. - have a critical understanding of the principles of operation and design of photovoltaic modules. - be able to compare and evaluate methods for the fabrication of photovoltaic modules, including performance and manufacturing issues.
1. Physics of Solar Cell Devices: - Solar spectrum, solar constant and air mass. - Important semiconductors. Important solar cell devices. - Drude theory. Breakdown of classical theory. Quantum theories of conduction: E-k curves, energy bandgap and effective masses, direct and indirect transitions. - Carrier statistics in equilibrium - intrinsic and extrinsic behaviour. - Carrier transport, mobilities and diffusion coefficients, scattering mechanisms. Hall effect. - Non-equilibrium behaviour: direct, indirect and surface recombination, carrier lifetime and diffusion length. - Current density and continuity equations, examples of solutions. - Optical and thermal properties of semiconductors. Antireflection coatings. p-n junction in equilibrium: built in voltage, depletion region and depletion capacitance. Derivation of I-V characteristics in the dark. - Spectral response. Ideal diode under illumination: open circuit voltage, short circuit current, solar conversion efficiency, fill factor. - Variations of photocurrent and open circuit voltage with incident light intensity. Optimum energy bandgap of a solar cell. - Loss mechanisms. Introduction to tandem/ multijunction concepts. - Real diodes: recombination and generation in the depletion region, effects of series and leakage resistance on ideal behaviour. Schottky diodes and Ohmic contacts. Interface states. - Heterojunctions: Anderson model, current transport models, heterojunction window effect. - Effects of temperature and radiation on solar cell performance. 2. Solar Cell Fabrication Technologies - Introduction: Important semiconductors and solar cell devices. - Important semiconductor parameters. Effects of lattice vibrations, impurity atoms and other crystal imperfections on these parameters. - Purification of silicon: chemical, zone refining and gettering. Segregation coefficient. - Crystal growth: Bridgmann methods, Czochralski method and Floating Zone Methods. - Advanced epitaxial growth methods: MBE, MOCVD, LPE AND VPE. - Low cost thin film deposition methods: thermal evaporation methods, sputtering methods and wet chemical methods, e.g electrodeposition, autocatalytic deposition, spray pyrolysis and screen printing. - Compensation doping: alloying, solid state diffusion and ion implantation. Dielectric deposition - thermal oxidation of silicon, LPCVD and PECVD silicon oxide and nitrides. - Photolithography. Etching - wet and dry methods. - Overview of characterisation techniques for semiconductor materials and cells. - Overview of design of silicon, III-V and thin film solar cells for terrestrial and space applications and the design and fabrication of photovoltaic modules made from these cells.
S.M.Sze and Kwok K. Ng: Physics of Semiconductor Devices, Wiley, 2006 Lewis Fraas and Larry Partain (eds): Solar Cells and Their Applications, Second Edition, Wiley, 2010. Journals of „Solar Energy Materials and Solar Cells" and „Progress in Photovoltaics“. Proceedings of IEEE Photovoltaic Specialist Conferences. Proceedings of European Photovoltaic Solar Energy Conferences.
|Language of instruction||English|
|Duration (semesters)||1 Semester|
|Modullevel / module level||MM (Mastermodul / Master module)|
|Modulart / typ of module||je nach Studiengang Pflicht oder Wahlpflicht|
|Lehr-/Lernform / Teaching/Learning method|
|Vorkenntnisse / Previous knowledge|
|Examination||Time of examination||Type of examination|
|Final exam of module||
At the end of the semester.
Written exam (60%, 3 hours) Laboratory Reports (40%)
|Workload attendance||0 h|