This tutorial is intended for young researchers (students and postgraduates within three years of degree completion) who are active in the field of thin-film solar cells, and would like to learn the fundamentals of characterization methods that are being used in research and development of these materials and devices. All presentations will be given (mostly) by young, yet experienced researchers who are active in the characterization of Si-, III–V-, chalcogenide-, kesterite-, as well as perovskite-based solar cells. Although these materials will be discussed as model systems, the presentations will primarily focus on the characterization and simulation techniques and thus should be of interest to participants from other symposia as well.
8:30 am—Electrical Device Characterization and Modeling of Thin-Film Solar Cells
Mike Scarpulla, The University of Utah
The tutorial includes a discussion of I–V and C–V DC analyses, AC characterization (CV, DLCP, DLTS and related techniques), localized state and band-structure-related responses; simulations using 1D solvers such as SCAPS and extensions to 2D; “hands-on” simulation demonstration.
10:30 am—Soft X-Ray and Electron Spectroscopies: Investigating the Chemical and Electronic Structure of Surfaces and Interfaces
Dirk Hauschild, Karlsruhe Institute of Technology
The tutorial gives an introduction to several soft x-ray and electron characterization techniques, including x-ray (XPS) and UV (UPS) photoelectron spectroscopy, inverse photoemission spectroscopy (IPES), x-ray excited Auger electron spectroscopy (XAES) and x-ray emission spectroscopy (XES). It includes a discussion of experimental requirements, information content, as well as data analysis and interpretation.
Examples of how the techniques can be used to determine the electronic and chemical structure of surfaces and interfaces in thin-film photovoltaic devices will be given.
1:30 pm—Time-Resolved Terahertz Spectroscopy on Energy Materials
Hannes Hempel, Helmholtz-Zentrum Berlin für Materialien und Energie
An introduction to measurement, analysis and application of time-resolved terahertz spectroscopy (TRTS) is presented. Determination of charge-carrier mobility, bulk lifetime and surface recombination velocity will be demonstrated on the example of perovskites, kesterites and metal oxides, as well as the impact of these key properties on solar-cell efficiencies. A comparison of TRTS to alternative measurement techniques will be included.
3:00 pm—Atomic Structure of Solar Materials by High-Resolution STEM and In Situ Microscopy
Chen Li, Electron Microscopy for Materials Science, University of Antwerp
An introduction to scanning transmission electron microscopy and the accompanying analytical techniques including atomic number contrast annular dark-field imaging, electron energy loss spectroscopy (EELS) and energy dispersive x-ray spectroscopy (EDX) will be presented. The focus will be the application of these techniques on understanding structure and composition in solar materials, with examples from CdTe and CIGS solar cells. In addition, a state-of-the-art in situ heating technique will be discussed as a powerful means of understanding solar materials growth.
4:00 pm—Atomistic Modeling of Defects in Materials
Kyoung Eun Kweon, Lawrence Livermore National Laboratory
Understanding defects and their roles in determining materials properties will be presented. A demonstration on how to compute thermodynamic and kinetic properties of (point) defects and defect complexes, particularly in Cu(In,Ga)Se2 will be included, as well as a discussion on how atomistic calculations can be used to interpret/understand experimental observations.