Physics of Thin Films: Advances in Research and Development, Volume 12 reviews advances that have been made in research and development concerning the physics of thin films. This volume covers a wide range of preparative approaches, physics phenomena, and applications related to thin films. This book is comprised of four chapters and begins with a discussion on metal coatings and protective layers for front surface mirrors used at various angles of incidence from the ultraviolet to the far infrared. Thin-film materials and deposition conditions suitable for minimizing reflectance changes with angle of incidence are described, along with novel oxide protective coatings with enhanced chemical stability and mechanical durability. The next chapter offers a comprehensive treatment of photoemissive materials. After giving a rather detailed review of the physics of photoemission, the main classes of thin-film photoemitters, including Ag-O-Cs, alkali antimonides, and negative-electron affinity photocathodes, are considered. A description of field-assisted cathodes potentially suitable for wavelengths beyond 1.1 micrometers, such as transferred-electron structures and field-emission arrays, is also given. The reader is then introduced to spray pyrolysis and the solution growth technique for chemical solution deposition of inorganic films. This text concludes with a chapter on plasma-enhanced chemical vapor deposition of thin films, paying particular attention to the experimental conditions required for a range of element and compound materials as well as some of the unusual film properties and structures achieved by this approach. This monograph will be useful to students and practitioners of physics, especially those interested in thin films.