The chemical and electronic properties of a solid can be measured non-destructively by analyzing the velocity of escaping electrons ejected from the material excited by X-rays. For most commercial laboratory-based soft X-ray sources, the majority of escaping electrons come from the topmost layers of the material making it a sensitive probe of the surface chemistry. Although surfaces are extremely important for many applications in catalysts and electronic devices, the chemistry at the surface is often distinctly different from the bulk underneath. Employing harder X-rays increases the percentage of electrons escaping from deeper within the material, but such bulk studies have thus far been limited to dedicated National facilities. Recent advances in new high-performance hard X-ray sources and detectors enable comparable bulk-sensitive measurements within a university laboratory setting thereby presenting a cost-effective means of increasing access to this emerging technique. The increased non-destructive chemical depth-profiling enables new insight into how buried layers within real device architectures evolve during operation, such as transistors, solar cells and batteries. The new instrument is accessible for academic and industry users across the U.S.A. The project integrates the instrument into various existing recruitment and educational programs at Binghamton University for increasing STEM retention and developing the workforce in next-generation technologies for energy harvesting, storage and efficiency.
This project provides a novel laboratory-based HArd X-ray Photoelectron Spectroscopy (HAXPES) system for non-destructive chemical analysis of real materials and devices at Binghamton University. HAXPES studies at Synchrotron facilities are capable of precise chemical and electronic measurements at previously inaccessible regions of real materials and devices. The laboratory-based HAXPES instrument consists of a novel monochromatic Ga K-edge liquid jet x-ray source (9.25 KeV) enabling core and valence band studies with sampling depths up to 60 nm. This instrument dramatically increases access to this technique beyond the handful of Synchrotron-based HAXPES systems currently operational worldwide. Working with Federally funded centers at Binghamton and partnering institutions across the U. S. A. (both academic and industrial) this project is developing in-situ and operando HAXPES capabilities for studying active layers and buried contacts within next-generation transistors and (photo-)electrochemical cells during their operation. The HAXPES instrument is housed in a dedicated user facility for access to wider scientific community. The HAXPES system is integrated into several educational and training programs at Binghamton, including an undergraduate course examining the aesthetics of archeological artifacts within the context of their chemical and physical properties.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
