{"corpus_id":139797124,"paper_sha":"c1abb64c4434e3d5c97f025c17db82c95ec69c3f","doi":"10.1016/J.APSUSC.2018.04.226","arxiv_id":null,"pmid":null,"pmcid":null,"mag_id":2799442935,"dblp_id":null,"acl_id":null,"title":"Reliable determination of chemical state in x-ray photoelectron spectroscopy based on sample-work-function referencing to adventitious carbon: Resolving the myth of apparent constant binding energy of the C 1s peak","year":2018,"publication_date":"2018-09-01","venue":"Applications of Surface Science","journal":{"name":"Applied Surface Science","pages":null,"volume":null},"journal_issn":null,"journal_title":null,"publication_types":["Review"],"pubmed_pub_types":null,"s2_fields_of_study":["Materials Science","Chemistry"],"reference_count":30,"citation_count":1258,"influential_citation_count":16,"is_open_access":false,"arxiv_categories":null,"arxiv_license":null,"arxiv_journal_ref":null,"mesh_headings":null,"chemicals":null,"comments_corrections":null,"source_flags":1,"s2_open_access_pdf_url":null,"s2_open_access_landing_url":null,"s2_open_access_license":null,"s2_open_access_status":null,"pmc_open_access_pdf_url":null,"pmc_open_access_landing_url":null,"pmc_open_access_license":null,"pmc_open_access_status":null,"unpaywall_open_access_pdf_url":null,"unpaywall_open_access_landing_url":null,"unpaywall_open_access_license":null,"unpaywall_open_access_status":null,"abstract":"Abstract The accuracy of chemical-state determination by x-ray photoelectron spectroscopy (XPS) used in contemporary advanced materials research relies on a trustworthy binding energy (BE) referencing method. The C 1s peak corresponding to C C/C H bonds of adventitious carbon (AdC), present on a majority of air-exposed samples, is most commonly employed for this purpose, irrespective of whether samples are electrically conducting or not. Contrary to conventional practice, which takes the BE of C 1s peak of AdC as a constant, we find that the C 1s peak position E B F varies over an alarmingly large range, from 284.08 to 286.74 eV, depending on the substrate, for nearly a hundred predominantly thin-film samples comprising metals, nitrides, carbides, borides, oxides, and oxynitrides. Our consistent measurements also show that, independent of materials system, E B F of the C 1s peak is closely correlated to the sample work function ϕ SA , such that the sum E B F + ϕ SA is constant, indicating that the electronic levels of the AdC layer align to the vacuum level, rather than to the Fermi level as commonly assumed. This phenomenon can be understood given that the AdC layer is not an inherent part of the analyzed sample and that the interaction to the substrate is weak, showing in that a common Fermi level is not established at the interface. Thus, a straightforward complementary measurement of ϕ SA enables using the C 1s peak of AdC for the purpose of BE–scale calibration for samples exhibiting decent electrical conductivity. This new practice resolves problems associated with the conventional method and allows for more reliable bonding assignments. It is thus advisable that both ASTM and ISO XPS referencing guides relying on the use of AdC should be reviewed.","claims":[{"public_id":"cl_9ba04cde0e015a0eb7e719b779fe6ef8","status":"active","text":"Complementary measurement of sample work function enables reliable use of the adventitious carbon C 1s peak for binding energy referencing in electrically conducting samples.","confidence":0.9,"contributors":[{"id":171,"public_id":"b9tnx83g25","public_label":"eunsjani (b9tnx83g25)","roles":["extraction"],"url":"https://sah.borca.ai/u/b9tnx83g25"},{"id":136,"public_id":"3c2apqe3ut","public_label":"Anonymous (3c2apqe3ut)","roles":["review"],"url":"https://sah.borca.ai/u/3c2apqe3ut"},{"id":17,"public_id":"322360f1c1","public_label":"Killer Whale (322360f1c1)","roles":["review"],"url":"https://sah.borca.ai/u/322360f1c1"}],"url":"https://sah.borca.ai/claims/cl_9ba04cde0e015a0eb7e719b779fe6ef8"},{"public_id":"cl_f86f0d593da4ac36ac2dd60b53c07294","status":"active","text":"The C 1s peak position of adventitious carbon correlates with sample work function such that their sum is constant, indicating the adventitious carbon layer aligns to the vacuum level rather than the Fermi level.","confidence":0.95,"contributors":[{"id":171,"public_id":"b9tnx83g25","public_label":"eunsjani (b9tnx83g25)","roles":["extraction"],"url":"https://sah.borca.ai/u/b9tnx83g25"},{"id":136,"public_id":"3c2apqe3ut","public_label":"Anonymous (3c2apqe3ut)","roles":["review"],"url":"https://sah.borca.ai/u/3c2apqe3ut"},{"id":17,"public_id":"322360f1c1","public_label":"Killer Whale (322360f1c1)","roles":["review"],"url":"https://sah.borca.ai/u/322360f1c1"}],"url":"https://sah.borca.ai/claims/cl_f86f0d593da4ac36ac2dd60b53c07294"},{"public_id":"cl_454ba278066967092b057aacd8cdc4fc","status":"active","text":"The C 1s peak position of adventitious carbon varies from 284.08 to 286.74 eV depending on substrate across nearly a hundred predominantly thin-film samples, contradicting the conventional assumption of constant binding energy.","confidence":0.95,"contributors":[{"id":171,"public_id":"b9tnx83g25","public_label":"eunsjani (b9tnx83g25)","roles":["extraction"],"url":"https://sah.borca.ai/u/b9tnx83g25"},{"id":136,"public_id":"3c2apqe3ut","public_label":"Anonymous (3c2apqe3ut)","roles":["review"],"url":"https://sah.borca.ai/u/3c2apqe3ut"},{"id":17,"public_id":"322360f1c1","public_label":"Killer Whale (322360f1c1)","roles":["review"],"url":"https://sah.borca.ai/u/322360f1c1"}],"url":"https://sah.borca.ai/claims/cl_454ba278066967092b057aacd8cdc4fc"}],"concepts":[{"public_id":"co_101fbfa69d1a84496fa38a31c06ae410","status":"active","name":"Fermi level alignment","description":"The conventional assumption that adsorbate electronic levels equilibrate with the substrate Fermi level, establishing a common Fermi level at the interface.","types":["phenomenon"],"aliases":[],"contributors":[{"id":171,"public_id":"b9tnx83g25","public_label":"eunsjani 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