October 24, 2017
Abstract: I will discuss some approaches to subsurface microscopy and spectroscopy in applications to thin-film solar cells and resistive switching devices. Thin film solar cells are based on polycrystalline materials such as CdTe or organic-inorganic perovskites that are structurally and electronically non-uniform. To effectively mitigate the recombination sources and further boost the efficiency in such systems, it is highly desirable to understand how the local properties of interfaces (p-n junction, contacts) and microstructure (composition variation, grain boundaries) are determined by the processing conditions and affect the overall photoelectrical properties of devices. Resistive switching devices can be used as nanoelectronic memories and as components of future neuromorphic computer architectures. The complex nature of the switching in these devices, speculated to involve coupling of chemical, electrical, and thermal fields has stymied a comprehensive understanding of the process. To characterize some properties of such devices under operation, one can use a local stimulus such as an electron or optical beam with variable penetration depth to the region of interest and measure electrical, optical or thermal responses. Meaningful interpretation of the data often requires a development of custom modeling tools and complementary measurement techniques.
Bio: Nikolai Zhitenev is the Group Leader at the Center for Nanoscale Science and Technology (CNST) at NIST. He received an M.S. degree in Physics from the Moscow Institute of Physics and Technology, Russia, and a Ph.D. degree in Condensed Matter Physics from the Institute of Solid State Physics, Russia. Nikolai was an Alexander von Humboldt Fellow at the Max-Planck Institute for Solid State Physics, Stuttgart, Germany, and then a Postdoctoral Fellow at the Massachusetts Institute of Technology. He then joined the staff at Bell Laboratories, Lucent Technologies, where his research focused on electronic transport in different physical systems, ranging from two-dimensional electron gasses in Si, Ge and GaAs, to semiconductor and metal quantum dots, to nanoscale molecular and polymer devices. Nikolai holds four patents and has over 90 publications in high-profile journals including Science, Nature, Physical Review Letters and Nano Letters. As a staff member in the CNST, Nikolai leads multiple projects related to the measurement of electronic properties of novel materials patterned into nanoscale devices, and to the development of local characterization of photovoltaic materials and devices.
For more information, please contact Professor Deirdre O’Carroll at 848-445-1496 or at firstname.lastname@example.org.