This book reviews up-to-date ideas of how the luminescence radiation in semiconductors originates and how to analyze it experimentally. The book fills a gap between general textbooks on optical properties of solids and specialized monographs on luminescence. It is unique in its coherent treatment of the phenomenon of luminescence from the very introductory definitions, from light emission in bulk crystalline and amorphous materials to the advanced chapters that deal with semiconductor nano objects, including spectroscopy of individual nanocrystals. The theory of radiative recombination channels in semiconductors is considered on a level of intuitive physical understanding rather than rigorous quantum mechanical treatment. The book is based on teaching and written in the style of a graduate text with plenty of tutorial material, illustrations, and problem sets at chapter ends. It is designed predominantly for students in physics, optics, optoelectronics and materials science.

Silicon is an abundant element and is produced in large quantities for the electronic industry. The falling price of this commodity also feeds the growth of solar photovoltaics (PV). However, solar cells (SCs) based on bulk semiconductors have quite limited maximum attainable performance. Therefore, new principles and materials are being investigated to build the third generation of SCs with improved conversion efficiency achieved by the optimized harvesting of the solar spectrum, improved carrier generation, better light management, etc. The unique properties of semiconductor nanostructures (tuning of optoelectronic properties by the quantum confinement effect, stronger interaction with light, etc.) can be exploited to fabricate novel types of high-efficiency solar cells. Here, again, silicon along with carbon and germanium (group IV elements) is about to play a major role. In view of the increasing research effort devoted to nanostructures' applications in PV, this book aims to provide a background to students and newcomer researchers as well as to point out some open questions and promising directions for future development. It presents a useful overview of group IV nanostructures for PV, which includes the theoretical background, presentation of main solar cell principles, technological aspects, and nanostructure characterization techniques, and finishes with the design and testing of prototype devices. It is not intended to be just a review of the most up-to-date literature, but the authors aim to provide an educative background of the field. All authors are renowned researchers and experienced teachers in the field of semiconductor nanostructures and photovoltaics.

Abstract: Thin layers of silicon nanocrystals (SiNC) in oxide matrix with optimized parameters are fabricated by the plasma-enhanced chemical vapor deposition. These materials with SiNC sizes of about 4.5 nm and the SiO2 barrier thickness of 3 nm reveal external quantum yield (QY) close to 50% which is near to the best chemically synthetized colloidal SiNC. Internal QY is determined using the Purcell effect, i.e. modifying radiative decay rate by the proximity of a high index medium in a special wedge-shape sample. For the first time we performed these experiments at variable temperatures. The complete optical characterization and knowledge of both internal and external QY allow to estimate the spectral distribution of the dark and bright NC populations within the SiNC ensemble. We show that SiNCs emitting at around 1.2-1.3 eV are mostly bright with internal QY reaching 80% at room temperature and being reduced by thermally activated non-radiative processes (below 100 K internal QY approaches 100%). The mechanisms of non-radiative decay are discussed based on their temperature dependence