My research centers around studying the growth of ultra-thin films by atomic-layer deposition and their characterization using advanced (nonlinear) optical diagnostics with an emphasis on their defects and non-idealities.

Currently I am focussing on the growth and characterization of 2D transition metal dichalcogenides (TMDs). This included the development of new ALD processes but also the further development of (advanced) diagnostics for these materials. Recently, I developed a new framework for texture characterization using Raman spectroscopy based upon new fundamental insight I obtained into the Raman response of nanocrystalline TMDs.

My PhD research encompassed mechanistic studies of the prototypical ALD processes for metal-oxide (thermal ALD of Al₂O₃) and for noble metal ALD (thermal ALD of Pt) using a new diagnostic: broadband sum-frequency generation (BB-SFG) spectroscopy. The surface chemistry during these processes was studied for the first time with this state-of-the-art technique which relies on the mixing of mid-IR and visible fs laser pulses. As such, SFG is a second-order nonlinear optical process making BB-SFG spectroscopy inherently surface sensitive. This property, combined with the all optical nature of BB-SFG, makes it ideally suited for in-situ studies of the surface chemistry. A purpose built setup was realized in the project and these BB-SFG studies revealed several key non-idealities in the growth mechanism of these well-studied prototypical ALD processes.

I also studied the surface chemistry of plasma-enhanced ALD of Al₂O₃ using ATR-FTIR spectroscopy at the Colorado School of Mines (CSM) and I worked on the characterization of the SiO₂/Si and Al₂O₃/Si interface relevant for nano-electronic and photovoltaic devices with phase-sensitive second-harmonic generation (SHG) spectroscopy. In conjunction with probing the electronic structure of the interface, SHG can also reveal and quantify the presence of built-in charges near these interfaces which is a key property for device fabrication.