This project aims at the development of advanced surface-sensitive characterization methods for PHOTOVOLTAICS (PV) MATERIALS RESEARCH within the framework of enhancement of mutual collaboration between the European host research group at TU-Eindhoven and the applicant's group of origin at UT-Dallas (USA). Nanolayer-engineering based on advanced deposition of ultra-thin oxides becomes an increasingly important subject in the current worldwide efforts to boost solar cells efficiencies. Advanced real-time non-destructive monitoring of reactions that take place on semiconductor surfaces during oxide nanolayer deposition is the key factor that allows precise control over the thin-film quality and functionality. (Non)linear vibrational spectroscopic methods are known to be especially powerful in surface and interface analysis at sub-monolayer coverage. To gain fundamental understanding of surface chemistry of ultra-thin oxides, we propose to develop broadband sum-frequency generation (BB-SFG), a novel nonlinear surface-specific vibrational spectroscopic technique for in-situ monitoring of PV-related deposition processes. The project will benefit from the unique combination of internationally acclaimed UT-Dallas group's expertise in application of vibrational spectroscopy to fundamental studies of surface phenomena and TU/e expertise in real-time optical monitoring of thin film deposition processes. In combination with infrared spectroscopic tools and other standard surface-sensitive techniques, we intend to explore the properties of atomic-layer deposited (ALD) oxides for (i) Si surface passivation of crystalline silicon (c-Si) solar cells and (ii) buffer layer engineering in Copper-Indium-(Gallium-) Diselenide (CI(G)S) thin-film solar cells. Intended at innovations in current and next generation photovoltaics, this project lies within the EU aims to strengthen European competitiveness in the global PV marketplace through technological leadership in R&D.