Study on the surface modification of Ta 2 O 5 bombarded by argon ions

Herein, X-ray photoelectron spectrometer (XPS), angle-resolved XPS (ARXPS), and atomic force microscopy (AFM) are used to study the surface changes of Ta 2 O 5 bombarded by Ar + ions with different energies. The results reveal that the Ar + bombardment of Ta 2 O 5 leads to a preferential sputtering of O atoms, which results in an imbalance in the Ta/O ratio on the material surface; and the formation of an “altered layer” composed of Ta 2 O 5 , Ta 1+ , Ta 2+ , Ta 3+ , and Ta 4+ . The Ta/O ratio increases from 0.34 to 0.55 with the sputtering time; however, it does not vary with ion energy. Before reaching a steady-state, the thickness of the altered layer increases with the sputtering time; however, after reaching a steady-state, the thickness of the altered layer does not exceed 3 nm. Concurrently, it increases with increasing sputtering energy. Further, AFM measurements reveal that low-energy Ar + bombardment leads to a slight increased surface roughness, which does not exceed the initial value (0.41 nm) by 25%.