Dresden 2020 – wissenschaftliches Programm
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CPP 9.8: Vortrag
Montag, 16. März 2020, 11:45–12:00, POT 112
Quantifying the Damage Induced by Monoatomic Ion Beam Etching during X-ray Photoemission Spectroscopy Depth Profiling of Conjugated Polymers — •Yvonne Jasmin Hofstetter1,2 and Yana Vaynzof1,2 — 1Integrated Center for Applied Physics and Photonics, Dresden, Germany — 2Center for Advancing Electronics Dresden, Dresden, Germany
X-ray photoemission spectroscopy (XPS) depth profiling using monoatomic Ar+ ion etching sources is commonly used to probe the vertical compositional profiles of polymer-based organic photovoltaic devices, focusing on compositional variations across interfaces and vertical phase separation within bulk-heterojunction active layers. The damage induced by the monoatomic etching is generally considered to be very shallow and is assumed to not significantly alter the XPS signal acquired at each step of the depth profile. Herein, we quantify the damage depth for a variety of conjugated polymers for monoatomic Ar+ ion beams of variable energy from 0.5 to 4 keV. Our results indicate that even when etching with the lowest available ion beam energy for as little as 3 s, the damage inside the polymer bulk material significantly exceeds the XPS probing depth (approx. 10 nm). We find that the damaged material exhibits a distorted composition which strongly changes the resulting XPS depth profile. In contrast, we find that Ar gas cluster ion beam etching is significantly less damaging and preserves compositional information demonstrating its superior suitability for XPS depth profiling of organic materials.