Title: Martin P Seah MBE—Shining a light on surface chemical analysis
Abstract: Martin Seah, one of the great metrologists of our time, passed away on 5 June 2021 aged 79. The journal Surface and Interface Analysis (SIA) was special to Martin; it was his publication homeland. The journal's first paper was the classic Seah and Dench paper (Seah, M.P. and Dench, W.A., Surf. Interface Anal., 1: 2–11, 1979) on inelastic mean free paths, and it is fitting that this special issue should contain Martin's last paper on the metrology of the OrbiSIMS. In this Special Issue, we bring together a collection of 21 papers dedicated to his memory. This collection contains reminiscences, biographical accounts of Martin's considerable achievements, reviews and research articles from his friends and colleagues around the world. I would like to begin with some of my own happy memories. I joined Martin's group at the National Physical Laboratory (NPL) in 1991 as a fresh graduate with a degree in Physics from the University of Manchester. It was an incredible experience to join his research-intensive group and Martin took me on as his PhD student. He schooled me in the ways of doing good research, and we went on to spend three decades collaborating. It really was tremendous fun, and I am indebted to him for all his help and advice over the years. Martin had a delightful balance of razor-sharp intellect, a gentle manner and a wonderfully dry sense of humour. These gifts allowed him to ask his interlocutor the most penetrating and challenging of scientific questions in a way that put them simultaneously on the spot and at ease. This led to engaging and often entertaining debate. Science would advance with Martin often providing a new idea or critical insight. It has been over a decade now since Martin stopped travelling to international conferences but no matter where I am, Japan, the US or Europe people will come up to me to ask after Martin and say how much they miss those lively and entertaining discussions. It was a special talent of his that in my 30 years of research I have not seen the like. Martin was an outstanding communicator. At conferences, Martin would draw crowds so that the hall would be packed to over-flowing. Everyone would pray their talk would not be in one of the deserted parallel sessions! His genius allowed him to see through complexity and unpick the tangle of obfuscating data. With great panache, he would reveal this simplicity with a finale producing an elegant model that would encapsulate everything. Where there was darkness, he shone light, and the audience would all be wondering “why ever did we not see that!” He had picked up the phrase “to see how far the light shines” from Robert Kaarls at the International Bureau of Weights and Measures, the international centre of metrology, in Paris. Martin made it his life's work to see how far he could shine the light. We take his phrase “Shining a Light on Surface Chemical Analysis” for the title of this special issue. This is in fact the second special issue of SIA to pay tribute to Martin. In 2002, his NPL colleagues Colin Lea and Peter Cumpson characterised him in their editorial with “Cut him in half one way and, like a stick of Brighton rock, he reads SURFACE ANALYSIS. Cut him the other way he reads NPL.” We can now see how true this statement is by studying Martin's publications from his half-century career at the NPL (Figure 1A) for 6 key themes: AES, XPS, SIMS, AFM, ISO and VAMAS. The data are smoothed with a 5-year moving average for display. We conclude that, firstly, Martin had phenomenal impact across these surface analytical techniques and standardisation. Whilst he is most well-known for his metrology in the electron spectroscopies, AES and XPS, we see that he had major contributions in AFM and in the latter years his work on SIMS dominated. Interestingly, at the time of his 60th birthday and the official civil service “retirement” age, we see a substantial burst in activity in XPS and AES! Knowing Martin, I expect he had in mind a number of critical things he resolved to get sorted out. Another striking feature that speaks to the enduring nature of his research is that this was not so much “retirement” but more the transition into the second act where he became increasingly interested in sputtering by cluster ion beams. The summed publication output for all topics with time (Figure 1B) reveals the peaks in the scientific themes of international standardisation, AES and XPS, AFM and SIMS which is overlaid with his major prizes and awards: Henry Marion Howe Medal of the American Society for Metals (1978), Leslie Holliday Prize of the Materials Science Club (1981), Albert Nerken Award of the American Vacuum Society (1989), British Vacuum Council Medal and Prize (1995), Institute of Physics Duddell Medal and Prize (1996), United Kingdom Surface Analysis Forum (UKSAF) Rivière prize (1998), NPL Gold Achievement Award (2002) and the VAMAS distinguished service prize (2005), In 2018, Martin received an MBE National Honour for his work that established international standards in surface chemical analysis and supporting UK industry. Returning to this special issue, we start with a set of six personal tributes to Martin. Cedric Powell gives a wonderful insight into their correspondence over almost 50 years and a detailed biography of Martin's career establishing quantitative surface analysis and his influential work in international standardisation. John Grant's reminiscences are illustrated with wonderful photographs evoking memories of Martin at conferences and international meetings and Don Baer brings to life Martin's considerable impact through four vignettes. Colin Lea, his long-time friend and colleague at NPL, gives fond memories of their times at NPL. Wolfgang Unger and Toshiyuki Fujimoto pay tribute to Martin's foundation of the Surface Analysis Working Group (SAWG) at the Bureau International des Poids et Mesures (BIPM) in Paris—an important development establishing surface chemical analysis activity in the heartland of the SI system for measurement. We complete this set with the perspective from a former young group member and now an academic in China, Li Yang, which beautifully brings out Martin's nurturing side. We follow this with a set of research and review articles covering important topics in surface chemical analysis including SIMS, cluster ion beam sputtering, ambient mass spectrometry, XPS, hard XPS (HAXPES) and AES giving practical guidance and improvement in quantitative analysis—topics dear to Martin's heart. We begin with a paper that Martin had been working on when he became unwell and with the SARS-CoV-2 pandemic we had put on pause. With the growing number of OrbiSIMS instruments around the world, Martin was naturally concerned with ensuring repeatable and reproducible measurements between instruments. With my colleagues at NPL he had started looking in detail at the effect of two parameters, the target potential and collision cell pressure on relative and absolute secondary ion intensities. Martin had laid out much of the framework for this study but unfortunately died before its completion. From Martin, I picked up that we got peace when the “box file was closed” and the paper was published and so it was imperative to complete this paper. Somewhat like Mozart's Requiem, we completed the work with systematic new data sets and diving deeper into the metrology to ensure Martin would be satisfied with it. Lidija Matjačić et al. present this paper on OrbiSIMS metrology, which is probably Martin's last paper. I am quite sure Martin would be pleased at the result. We keep with the theme of SIMS and sputtering in the next five papers. Firstly, Peter Cumpson, whose early career was with Martin, and his colleagues report an elegant molecular dynamics study to determine the total sputtering yield of silicon by large gas clusters. The SIMS group at Manchester, now led by Nick Lockyer, present their latest developments in the use of chemically reactive gas cluster ion beams to boost sensitivity in SIMS by Matija Lagator et al. Cluster ion beams have been a transformational technology for SIMS and a topic of great interest to Martin. Another hot topic is the use of machine learning and information theory to help interpret complex data and Satoka Aoyagi report their most recent results using information entropy. Quantitative surface analysis was an enduring central theme for Martin. Alexander Shard, Ako Miisho and Satoka Aoyagi et al. study SIMS matrix effects in binary organic mixtures and demonstrate significant improvements in quantification using an empirical power law fit with a two-point calibration. Practical surface analysis was also a core topic for Martin; indeed, it is the title of his celebrated books. Adam Dundas and colleagues from the University of Nottingham, including Morgan Alexander, describe a method for the practically challenging issue of mounting particles for surface analysis without contamination from adhesive tape. We now transition from SIMS to XPS with three review articles. Martin was keenly interested in the latest developments in metrology that push the boundaries of what is possible and followed the work of his good friend and metrology comrade, Dae Won Moon, very closely. Moon et al. review their exciting developments to analyse living cells using ambient mass spectrometry and SIMS. John Watts and Robyn Goacher give a comprehensive guide to surface analysis of wood by XPS and ToF-SIMS with a special emphasis, as Martin would appreciate, on meaningful analysis! As remarked in the tributes earlier in this issue, Martin founded the Surface Analysis Working Group with an odyssey (the voyage is documented in detail in over 10 publications) to measure the amount of silicon dioxide on silicon expressed as a thickness with traceability to the SI. Motivated by these studies, Kyung Joong Kim reviews the use of a mutual calibration method for thickness measurement of ultrathin oxide films. Misha Zelzer et al. use a combined XPS and ToF-SIMS approach to correlate cell-adhesion with a molecular signature from a polymer surface with controlled amino acid and peptide content. An improvement in quantification enables the design of new biomaterials. Martin's interest in the electron inelastic mean free path (IMFP) goes back to that famous paper of his in the first issue of this journal back in 1979. It is, of course, a fundamental parameter for understanding the inelastic background in XPS and more recently HAXPS. Charlotte Zborowski and Martin's friend of many years, Sven Tougaard, present a theoretical study on how to choose the IMFP and inelastic scattering cross-sections for inelastic background analysis with the Quases-Tougaard software. Continuing this theme, David Cant et al. report a method for the rapid determination of theoretical relative sensitivity factors for HAXPES instruments with any instrument geometry and photon energy. The final three papers are from two long-term friends and colleagues of Martin; Jim Castle and John Grant. In Jim's tribute to Martin, he presents a unified scale for the Auger parameter that enables additional information on the polarizability of the material's structure to be obtained. John pays tribute with a brace of papers on derivative Auger spectra describing approximate and exact corrections for modulation effects and guidance on the optimum parameters if the derivative is done algorithmically. I would like to thank all the authors for their enthusiasm and timely contributions to this Special Issue and to the many reviewers who dedicated their time to give prompt and detailed reports so that we could complete this homage to Martin in good time. Please enjoy this very special issue of the journal. Dr Martin Seah MBE was an inspirational scientist who pioneered metrology for surface chemical analysis establishing international standards and the global equivalence of measurements. Martin, you made the light shine far and wide on surface chemical analysis. A light that will not go out. There is no associated data.
Publication Year: 2022
Publication Date: 2022-03-11
Language: en
Type: article
Indexed In: ['crossref']
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