This issue of ECS Transactions includes papers based on presentations from the symposium "Processes at the Semiconductor Solution Interface 8," originally held at the 235th ECS Meeting in Dallas, Texas, May 26-30, 2019.

The symposium consisted of four half-day sessions on topics at the forefront of semiconductor electrochemistry and solution-based processing including etching, patterning, passivation, porosity formation, electrochemical film growth, energy conversion materials, deposition, semiconductor surface functionalization, photoelectrochemical and optical properties, and other related processes. This issue of ECS Transactions contains 18 of the papers presented including invited papers by H. Föll (Christian-Albrechts University Kiel), J. N. Chazalviel (Ecole Polytechnique, CNRS), D. N. Buckley (University of Limerick, and Past President, ECS), J. D. Holmes (University College Cork), E. Chassaing (IRDEP, EDF-CNRS-ENSCP).

Since its inception in 1966, the series of numbered volumes known as Semiconductors and Semimetals has distinguished itself through the careful selection of well-known authors, editors, and contributors. The Willardson and Beer series, as it is widely known, has succeeded in producing numerous landmark volumes and chapters. Not only did many of these volumes make an impact at the time of their publication, but they continue to be well-cited years after their original release. Recently, Professor Eicke R. Weber of the University of California at Berkeley joined as a co-editor of the series. Professor Weber, a well-known expert in the field of semiconductor materials, will further contribute to continuing the series' tradition of publishing timely, highly relevant, and long-impacting volumes. Some of the recent volumes, such as Hydrogen in Semiconductors, Imperfections in III/V Materials, Epitaxial Microstructures, High-Speed Heterostructure Devices, Oxygen in Silicon, and others promise that this tradition will be maintained and even expanded.

Section 1 addresses the most recent developments in processes at the semiconductor-solution interface include etching, oxidation, passivation, film growth, porous semiconductor formation, electrochemical, photoelectrochemical, electroluminescence and photoluminescence processes, electroanalytical measurements and related topics on both elemental and compound semiconductors. Section 2 addresses the most recent developments in compound semiconductors encompassing advanced devices, materials growth, characterization, processing, device fabrication, reliability, and related topics.

This issue of ECS Transactions contain the most recent developments in compound semiconductors encompassing advanced devices, materials growth, characterization, processing, device fabrication, reliability, and other related topics, as well as the most recent developments in processes at the semiconductor/solution interface including etching, oxidation, passivation, film growth, electrochemical and photoelectrochemical processes, electroluminescence, photoluminescence, and other related topics.

This ninth volume in the series concentrates on in situ spectroscopic methods and combines a balanced mixture of theory and applications, making it highly readable for chemists and physicists, as well as for materials scientists and engineers. As with the previous volumes, all the chapters continue the high standards of this series, containing numerous references to further reading and the original literature, for easy access to this new field. The editors have succeeded in selecting highly topical areas of research and in presenting authors who are leaders in their fields, covering such diverse topics as diffraction studies of the electrode-solution interface, thin organic films at electrode surfaces, linear and non-linear spectroscopy as well as sum frequency generation studies of the electrified solid-solution interface, plus quantitative SNIFTIRS and PM-IRRAS. Special attention is paid to recent advances and developments, which are critically and thoroughly discussed. The result is a compelling set of reviews, serving equally well as an excellent and up-to-date source of information for experienced researchers in the field, as well as as an introduction for newcomers.

The first source on this expanding analytical science, this reference explores advances in the instrumentation, design, and application of techniques with electrogenerated chemiluminescence (ECL), examining the use and impact of ECL-based assays in clinical diagnostics, life science research, environmental testing, food and water evaluation, and th