Oxidation and stoichiometry studies of pulsed laser ablation plasmas

Pulsed Laser Deposition (PLD) is a versatile technique to deposit complex materials. However, knowledge on the PLD process is based largely on experimental research examining what parameters appear to provide the best result for a specic setup and material. The goal of our research is to progress towards an improved understanding and control of PLD for scaling up to large-area deposition while maintaining full control on lm growth, i.e., to the level of atomic precision.
To map the spatial and temporal evolution of the ablation plasma, we built a PLD test system that allows for in-situ laser induced uorescence imaging and absorption spectroscopy measurements. From this, it is possible to generate a 3D map of the absolute material ux towards the substrate, which is essential for obtaining a fundamental understanding of the plasma chemistry and evolution.
The stoichiometry of the plasma plume, the oxidation of specic species and the propagation speed of the material can all be controlled by varying the ablation laser uency, the background pressure and the background gas mixture (typically Ar and O2). This in turn allows us to ne-tune the properties of the layers that are grown with these plasmas. Here, we present our recent results on the oxidation and stoichiometry of species in plasmas created by laser ablation of SrTiO3 and LaAlO3.