Current trends in near ambient pressure x-ray photoelectron spectroscopy (NAP-XPS). Degree of reporting of instrument parameters

A thorough understanding of x-ray photoelectron spectroscopy (XPS) results requires well-reported data collection and analysis parameters. Near ambient pressure (NAP)-XPS instrument parameters are not always reported as thoroughly as they could be in the scientific literature. This paper examines parameter reporting within the main bodies of NAP-XPS papers published from 2021 to 2023. Parameters studied include the analyzer, photon flux, x-ray source and energy, spot size, pass energy, signal integration parameters, incident angle, substrate temperature, aperture size and distance, background gas, and fitting parameters such as the background and synthetic peak shapes. On average, less than 50% of these instrument parameters are reported within the main bodies of papers, although some parameters are reported better than others. For instance, the analysis chamber pressure is reported 94% of the time, while signal integration parameters are only reported 6% of the time. Over 50% of NAP-XPS experiments are conducted at synchrotrons. Most NAP-XPS papers (92%) contain fitted data, but fewer than 50% of these papers reported peak fitting parameters. Fewer than 5% of NAP-XPS studies are operando. While this study reveals some shortcomings in reporting, because not all NAP-XPS instrument parameters are of equal importance in all experiments, and because parameter reporting also took place in the supporting information of some papers, papers that did not report all possible parameters in their main bodies do not necessarily constitute irreproducible work. Some of the experimental details and data related to a study in the supporting information sections of papers should often be included within the papers themselves, perhaps as appendices.