Physics of Solar Cell Devices (or equivalent course in basics of semiconductors and P/N junctions on crystalline silicon)
After the course the student should be able to:
Provide a critical view on thin film technologies and their position with respect to the leading crystalline silicon
Describe the operating principles of various types of solar cells structures: P-N junction, P-I-N, Heterojunction solar cells
Possess a detailed knowledge of thin film deposition processes and characterization techniques.
Determine the efficiency of solar cells based on their opto-electrical modeling
Understand the various steps involved in the value chain from materials to modules
Course main content
The course will focus on the two main families of materials at the basis of the second generation of solar cells, namely silicon thin films (amorphous, microcrystalline, thin film crystalline, and alloys with O, C and Ge) and chalcogenides (CdTe and CIGS). It will provide the basis for a deeper understanding of the materials used to build up the solar cells, their structural and electrical characterization, as well as provide the basis to foresee the future of thin film PV in a very competitive arena. Professors will present the solar cell technologies and give the elements of material science to understand both fundamental and technological aspects of Thin-Film Photovoltaics.
The course consists of 9 units of four hours divided as follows:
Lecture 1: Introduction to the physics of solar cells: basics of photovoltaic conversion, thermodynamics of light to electricity conversion, fundamental key properties of photovoltaic materials and basic device structures, limits of photovoltaic conversion
Lectures 2-3: Solar cells based on II-VI compounds and chalcogenides (CdTe and Copper indium gallium diselenide) : basics of polycrystalline compound semiconductors, devices, fabrication processes and manufacturing
Lectures 4-5: Silicon thin film technology: plasma enhanced chemical vapor deposition as a versatile tool to deposit silicon thin films and synthesize nanomaterials which are combined in various kinds of solar cell structures (homojunctions, heterojunctions, radial junction solar cells,...) in order to achieve high efficiency at low cost
Lecture 6: High efficiency concepts for solar cells: III-V and multijunctions materials and devices, up and down conversion, nanophotonics. The lecture will also include an introduction to modeling of solar cells
Lecture 7: Optical properties of solar cells: Students will learn from the basic concepts for the reduction of the spectral reflectance to more advanced nanostructures. In particular, the focus will be on periodic structures such as diffraction gratings or photonic crystals, the exploitation of one dimensional nanowires or metallic nanoantennas, progressive techniques based on plasmonic or photonic effects ...
Lecture 8: Electronic characterization of thin films, based on examples from silicon thin films. 1) Measurements in planar configuration including dark conductivity vs temperature, steady-state photoconductivity, modulated photocurrent, constant photocurrent method and steady-state photocarrier grating. 2) Measurements in diode configuration including admittance spectroscopy, quasi steady-state measurements as a function of bias, frequency and temperature, quasistatic capacitance and transient capacitance (ICTS and DLTS, photocapacitance). The principle of each technique and the use to extract material or interface parameters will be described
Lecture 9: Photovoltaic modules and systems: making modules out of cells; strategies for getting the maximum power out of the module thanks to power electronics; PV in isolated areas and related storage issues; grid connected systems
Examination and requirements for final grade
Students are evaluated based on a final written exam plus homework based on critical reading and presentation of research articles. Each student gets an article to review and present to the class.
Pere ROCA i CABARROCAS, Ecole polytechnique
Jean François GUILLEMOLES, Jean Paul KLEIDER, Martin FOLDYNA, Olivier BETHOUX
Langue du cours : Anglais
Credits ECTS : 4