Ricerc@Sapienza

The Kaufman source acquired allows varying the proton beam energy from 10 to 1200 eV with a high degree of reproducibility and control. The same applies to the dose of incorporated protons. These very important parameters are typically hard to control by other systems, such as plasma sources or electrochemical methods. Indeed, Kaufman sources are configured to have the region of gas ionization physically separate from the intended target, avoiding exposure of the samples to intense and potentially damaging electric fields. This turns out to be especially critical in ultra-thin samples, such as 2D crystals, and nanostructures, such nanowires and quantum dots. The source is installed in the Spectro-Microscopy Laboratory (SMART) of the Amaldi Research Center at the Physics Department. SMART features a unique experimental configuration, where electron spectroscopy characterization tools in ultra-high-vacuum (UHV) micro-Raman and micro-PL setups are integrated, enabling us to have an in-situ picture of the evolution of the optical and electronic properties of the samples after H treatment with sub-micron spatial resolution. This is an unprecedented experimental advancement that will permit to understand in detail the mechanisms underlying many important phenomena like catalysis, atomic layer exfoliation, and semiconductor surface reconstruction, to cite a few exciting examples.