A method to prevent the reduction of CuO formed on Cu metal during x‐ray photoelectron spectroscopy analysis is presented. When a bias voltage of ‐250 V was applied to the sample surface in the case of non‐monochromatic Mg Kα1,2 irradiation, the reduction of CuO to the lower oxide (Cu2+Cu+) was suppressed by 80–90% as compared with ordinary non‐monochromatic x‐ray irradiation. The degree of CuO reduction is the same as in the case of monochromatic Al Kα x‐ray irradiation. It was found that slow electrons generated from the x‐ray window and photoelectrons emitted from the surface by x‐ray irradiation cause the reduction. As the reduction can be minimized by applying a bias voltage to the surface, the bias voltage method is very effective for preventing CuO reduction.
The electrospray droplet impact (EDI), in which the charged electrospray water droplets are introduced in vacuum, accelerated, and allowed to impact the sample, is applied to polymethylmetacrylate (PMMA). The secondary ions generated were measured by an orthogonal time-of-flight mass spectrometer. In EDI mass spectra for PMMA, fragment ions originating from PMMA could not be detected. This is due to the fact that the proton affinities of fragments formed from PMMA are smaller than those from acetic acid contained in the charged droplet. The x-ray photoelectron spectroscopy spectra of PMMA irradiated by water droplets did not change with prolonged cluster irradiation, i.e., EDI is capable of shallow surface etching for PMMA with a little damage of the sample underneath the surface.
500 eV Ar+ ion impact and the electrospray droplet impact (EDI), in which the charged electrospray water droplets are introduced in vacuum, accelerated and allowed to impact the sample, are applied for etching of polyimide (PI). After the bombardment, x-ray photoelectron spectroscopy (XPS) was applied to the surface analysis. Although oxygen and nitrogen are selectively etched by Ar+ ion impact, the XPS spectra did not change with prolonged charged water droplets irradiation, i.e., EDI is capable of shallow surface etching for PI with little damage of the sample after irradiation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.