Internal Photoemission Spectroscopy: Principles and Applications

The monographic book addresses the basics of the charge carrier photoemission from one solid to another - the internal photoemission, (IPE) - and different spectroscopic applications of this phenomenon to solid state heterojunctions. This is the first book in the field of IPE, which complements the conventional external photoemission spectroscopy by analysing interfaces separated from the sample surface by a layer of a different solid or liquid. IPE is providing the most straightforward and, therefore, reliable information regarding the energy spectrum of electron states at interfaces. At the same time, the method provides the unique capability of analysing the heterostructures relevant to the modern micro- and nano-electronic devices as well as new materials involved in their design and fabrication. In addition to the discussion of fundamental physical and technical aspects of IPE spectroscopic applications, several 'hot' topics are addressed. These include development of new insulating materials for advances Si MOS technology (both high-k gate insulators and low-k dielectrics for interconnect insulation), metal gate materials, development of heterostructures based on high-mobility semiconductors, etc. Thanks to a considerable activity in this field over the last few years, the recent results concerning band structure of most important interfaces involving novel materials can now be documented.

Photoemission of charge carriers from one solid into another (the internal photoemission, IPE) represents the counterpart of the well-known photoemission into vacuum (the external photoemission) which constitute a base for wide spectrum of surface spectroscopy techniques. In a similar spirit, IPE represents a powerful tool of electron state spectroscopy at interfaces and in heterostructures combining the interface sensitivity typical of the conventional photoelectron spectroscopy and sufficient depth and the non-destructive character of analysis characteristic to the optical spectroscopy. The book provides a reader with the first elaborate description of fundamental and technical aspects of the IPE spectroscopy as well as with overview of recent achievements in the field of novel material systems for electronic application in micro- and nano-devices.
Following an introduction indicating the need for interface electron spectroscopy, the physical grounds of IPE are discussed. In addition, the practical features in realization of IPE measurements are presented. Next, the approaches to characterization of electron states at interfaces are presented and illustrated by original experimental results (Chapters III and IV). This part is complemented by the analysis of (photo) injection methods aimed at characterization of localized states in thin layers of solids and at their interfaces (Chapters V-VIII). The band alignments at semiconductor (Chapter IX) and metal interfaces (Chapter X) are surveyed as well as behaviour of electrically active defects in thin dielectric films (Chapter XI) in relationship to development of high-permittivity insulator technology for the advanced electronic devices.
The Internal Photoemission Spectroscopy will serve as a practical guide for the researches in the field and also provide them with most up-to-date reference material concerning fundamental electronic properties of interfaces and thin sold films. It may also be used as introductory book for graduate students working on different aspects of spectroscopic characterization of interfaces or taking advanced courses on semiconductor physics and materials characterization.