Springer Series in Surface Sciences 73 Yoshihiro Momose Exoemission from Processed Solid Surfaces and Gas Adsorption Springer Series in Surface Sciences Volume 73 Series Editors Gerhard Ertl, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany Hans Lüth, Peter Grünberg Institute, Forschungszentrum Jülich GmbH, Jülich, Germany Roberto Car, Department of Chemistry, Princeton University, Princeton, NJ, USA Mario Agostino Rocca, Dipartimento di Fisica, Università degli Studi di Genova, Genova, Italy Hans-Joachim Freund, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany Shuji Hasegawa, Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo, Japan This series covers the whole spectrum of surface sciences, including structure and dynamics of clean and adsorbate-covered surfaces, thin films, basic surface effects, analytical methods and also the physics and chemistry of interfaces. Written by leading researchers in the field, the books are intended primarily for researchers in academia and industry and for graduate students. Yoshihiro Momose Exoemission from Processed Solid Surfaces and Gas Adsorption Yoshihiro Momose Department of Materials Science Ibaraki University Hitachi, Japan ISSN 0931-5195 ISSN 2198-4743 (electronic) Springer Series in Surface Sciences ISBN 978-981-19-6947-8 ISBN 978-981-19-6948-5 (eBook) https://doi.org/10.1007/978-981-19-6948-5 © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023 This work is subject to copyright. All rights are solely and exclusively licensed by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Singapore Pte Ltd. The registered company address is: 152 Beach Road, #21-01/04 Gateway East, Singapore 189721, Singapore Preface The purpose of this book is to introduce readers to the study of electron emission phenomena of metals and semiconductors, in the context of surfaces excited by various methods, and corresponding applications to surface chemical technology. This electron emission substantially differs from well-known types of thermionic emission (high temperature), photoemission, and field emission (high electric field) from clean surfaces. Such electron emission has been widely known by nomencla- ture such as the Kramer effect, exoelectron emission, and exoemission. In this book, we used exoemission. Exoemission occurs from solid surfaces that are subjected to various processes and has received substantial attention in industrial fields such as tribology (friction, wear, and lubrication). Exoemission occurs at low temper- atures, as measured with a Geiger–Müller (GM) counter. Professor Y. Tamai of Tohoku University has emphasized the importance of the Kramer effect in the field of tribology. I have been inspired by his guidance. He was the adviser of my thesis and a long-term collaborator; we have continued corresponding research. The contents of this book are based mainly on papers published by my group and collaborators. This book is an introductory text that is suitable for senior undergraduate and post- graduate students in physics, chemistry, engineering, and metallurgy. Furthermore, I have attempted to render the book suitable for scientists and researchers in indus- trial laboratories, who are interested in the surface properties of solid materials. The general level of presentation has been kept elementary, with emphasis on the physical and chemical properties of solids, as well as adsorbed or deposited materials. Controlling the properties of the surfaces and interfaces of solid materials is pertinent to the functionality as well as the reliability of the surfaces of solid mate- rials. Processes at solid surfaces are important in industrial fields such as adhesion, tribology, catalysis, chemical processes, and corrosion. To achieve such function- ality and reliability, a solid surface must first be subjected to pretreatments—i.e., activated—by various processes. One often performs surface processing of solid materials (such as metals and semiconductors) by external processes such as (1) mechanical treatment, (2) thin-film coating, and (3) exposure to ionizing irradiation (such as ultraviolet light, plasmas, and ion as well as electron beams). These surface processes are termed excitation. Consequently, one introduces functional groups v vi Preface to the surface, and various types of lattice as well as electronic defects form in the vicinity of the surface. Furthermore, when placed under production sites after surface processing, oxygen, water vapor, and other environmental materials adsorb onto the surface. Engineering researchers must perform careful work to reproducibly impart the same properties to a surface; further efforts are required to develop technologies for monitoring surfaces and interfaces that are applicable for industrial use. After the aforementioned excitation, one usually stimulates the surface of solid materials by temperature and/or light irradiation and further applies an applied or accelerating voltage to the surface as well as rubbing the surface with a polymer rod. Such stimulations are conventionally termed thermally (temperature), optically or photo (light) stimulated electron emission, and the effect of applied voltage. Furthermore, we have developed two stimulation methods for photoelectron emis- sion: thermally assisted and temperature-programmed photoelectron emission; as well as the method of tribo-stimulated (rubbing) electron emission. Thus, by using these stimulation methods, we imparted a difference to the electron emission char- acteristics of the surfaces. In particular, this book reveals the electronic properties of the processed surfaces under the influence of adsorbed foreign materials. This book is composed of four parts and 12 chapters: Part I, Introduction, Chap. 1; Part II, EE Mechanism of Metals Subjected to Adsorption, Chaps. 2–4; Part III, Outline of Development of EE Research, Chaps. 5–7; and Part IV, TAPE, TPPE, TriboEE, and XPS Characteristics of Processed Surfaces, Chaps. 8–12. I hope that those who study the physics and chemistry of metal surfaces, as well as those who are engaged in science and technology research that is related to metal surfaces, will use or refer to the results described in this document from various perspectives. It is a pleasure to dedicate this book to the late Professor Y. Tamai, who inspired my interest in the subject and with whom I had the privilege of working. I thank my postgraduate and senior undergraduate students of Department of Materials Science of Ibaraki University (Hitachi campus), who have assisted me in performing studies and experiments. I wish to thank Dr. K. Nakayama and Dr. T. Sakurai, with whom I have collaboratively performed research that is related to exoemission and have given continued support and valuable comments over many years. I acknowledge Dr. I. Ohshima, with whom I have conducted research in the field of mechanical treatment of metallic solids. I also thank Dr. M. Takeuchi and Professor H. Mase, who have made many useful suggestions about applied physics and electronics and provided encouragement. I also thank Professor Y. Nishiyama and Professor T. Matsunaga, with whom I studied surface chemistry in Tamai’s laboratory, and for Dr. S. Mori, who has given me a lot of information about tribology research. Finally, I thank my wife Takako Momose for her support and encouragement for this research. Hitachi, Japan Yoshihiro Momose Contents Part I Introduction 1 Surface Phenomena and Exoemission ........................... 3 1.1 Pertinence of Exoemission to Surface Phenomena ............. 3 1.1.1 Involvement in Surface Chemical Technology ......... 3 1.1.2 Work Function and Analysis Methods of Electron Emission ........................................ 6 1.2 Exoemission Phenomena of Processed Surfaces .............. 9 1.2.1 Importance of Exoemission Studies for Processed Surfaces ......................................... 9 1.2.2 Historical Background ............................. 10 1.3 Exoemission Measurements of Processed Surfaces ............ 11 1.3.1 External Treatments and Terminology of Exoemission ................................... 11 1.3.2 Trend of Current Studies ........................... 12 1.3.3 Measurement Apparatus and Surface Cleanliness ...... 14 1.3.4 Origin of Exoemission ............................. 14 References .................................................... 15 Part II EE Mechanism of Metals Subjected to Adsorption 2 EE of Clean Metals: Adsorption of Mainly O and H O 2 2 in the UHV and HV ........................................... 21 2.1 Specification of Practical Surfaces .......................... 21 2.2 Development of Chemiemission ............................ 22 2.3 EE Attributable to Adsorption of Electronegative Gases ........ 26 2.3.1 EE During Oxidation of Cs Films Deposited on Ru .... 31 References .................................................... 33 3 EE from Metal Surfaces Covered with Oxide: Adsorption of Mainly O and H O and Oxide-Film Thickness ................ 35 2 2 3.1 OSEE Observed in the UHV and HV for Al O /Al ............ 35 2 3 vii viii Contents 3.2 EE Observed in Air for MgO/Mg, Al O /Al, and NiO/Ni ...... 42 2 3 3.3 EE Observed in Counter Gas for Oxide-Covered Metal Surfaces of Sn, Al, Fe, Ni, and Cu .......................... 46 References .................................................... 52 4 Effects of Organic Adsorption, Applied Voltage, Light Irradiation, and Catalytic Activity .............................. 53 4.1 Effect of Adsorption on OSEE from Al ...................... 53 4.2 Effect of AV and Light Intensity on OSEE from Al ............ 56 4.3 Relation Between EE and Catalytic Activity of Ag, Cu, and Pt .................................................. 62 References .................................................... 64 Part III Outline of Development of EE Research 5 Materials, EE Measurement, and EE Characteristics ............. 69 5.1 EE Measurement Methods and EE Data Analysis Methods ..... 69 5.2 Stimulation by Thermal, Optical, and Tribological Methods After Excitation .................................. 70 5.3 Nomenclature of EE Categorized by Stimulation Methods ...... 72 References .................................................... 73 6 TSEE Related to Plasma Treatment and Adsorption .............. 75 6.1 Outline of TSEE of Metal Surfaces After Plasma Treatment .... 75 6.2 Effect of Discharge, Adsorption, and Heat Treatment on TSEE from Metals ..................................... 78 6.2.1 TSEE from Spark-Discharged Fe Surfaces and Adsorption ................................... 78 6.2.2 TSEE from Oxidized and Plasma-Treated Ni Surfaces ......................................... 80 6.2.3 TSEE After Electric Discharge Treatment and Chemical Reduction of Cu Surfaces .............. 85 6.3 TSEE from Glass on Au Surfaces, Au, Ni, Si, and Graphite Subjected to Plasma Exposure; and XPS Analysis ............. 89 6.3.1 TSEE from Glass Deposited on Au Metal Surfaces .... 89 6.3.2 TSEE from Au and Ni Metal Surfaces to Exposed to Ar and O Plasma .............................. 92 2 6.3.3 TSEE from Ni Metal Surfaces Exposed to Ar and O Plasma ................................... 95 2 6.3.4 TSEE from Si Wafer Powder Exposed to Ar Plasma ... 97 6.3.5 TSEE from Graphite Exposed to CF , Ar, and O 4 2 Plasma .......................................... 103 References .................................................... 107 Contents ix 7 Effects of Blasting and Grinding Agents as Well as Cutting Fluids on TSEE from Mechanically Deformed Surfaces ........... 111 7.1 TSEE from Sandblasted Mild Steel and Ground Sand .......... 111 7.1.1 TSEE from Sandblasted Mild Steel and Adsorption of Organic Vapors ................................ 111 7.1.2 TSEE from Ground Sand Granules (Aluminosilicate) and Adsorption of Organic Vapors .......................................... 112 7.2 EE from Metals and Plastics Blasted or Ground with Abrasive Agents ..................................... 115 7.2.1 TSEE from Metals Blasted with Silicon Carbide (SiC) ............................................ 115 7.2.2 EE from Plastics Abraded with Al O and SiC ........ 117 2 3 7.3 TSEE from Metal Surfaces Subjected to Cutting and Grinding ............................................ 117 7.3.1 TSEE from Al Surfaces Cut with a Tool Steel and Effect of Cutting Fluids ........................ 117 7.3.2 EE from Metals During Cutting with WC and Friction ...................................... 126 7.3.3 TSEE Under Light Illumination from Low-Carbon Steel Surfaces Ground with Al O .................. 127 2 3 References .................................................... 132 Part IV TAPE, TPPE, TriboEE, and XPS Characteristics of Processed Surfaces 8 TAPE of Rolled and Scratched Fe Metal Surfaces ................ 135 8.1 Temperature Dependence of PE from Rolled Fe Surfaces ....... 135 8.2 Wavelength Dependence of PE from Rolled Fe Surfaces ....... 141 8.3 PE from Practical Fe Surfaces Scratched in Air, Water, and Organic Liquids ...................................... 148 8.3.1 PE in Temperature Scans of Scratched Fe Surfaces and XPS Analysis ................................. 148 8.3.2 Activation Energy of PE from Scratched Fe Surfaces ......................................... 148 8.3.3 PE in Wavelength Scans of Scratched Fe Surfaces ..... 153 8.4 Temperature Analysis of PE and XPS Data of Scratched Fe Surfaces .............................................. 156 References .................................................... 161 9 TAPE of Si Wafers ............................................ 163 9.1 Effect of Adsorption of O and H OonEEfromSi ........... 163 2 2 9.2 PE from Si Wafers and Activation Energy .................... 165 9.3 PE from Si Wafer Surfaces Implanted with H, Si, and Ar Ions ........................................ 168 References .................................................... 172