Shorter laser pulses improve spectroscopy

Rapid advances in reducing laser pulse duration to the femtosecond range have naturally been accompanied by corresponding advances in time-resolved spectroscopy of semiconductors. J. Shah`s Ultrafast Spectroscopy of Semiconductors and Semiconductor Nanostructures is a treatise on the complex dynamics following ultrashort photoexcitation of compound III-V semiconductors, with an emphasis on gallium arsenide. It is written at a level appropriate for graduate students and researchers in the field o

Shorter laser pulses improve spectroscopy

Ultrafast Spectroscopy of Semiconductors and Semiconductor Nanostructures

Jagdee¥Shah, Springer-Verlag, Berlin, 1996, 372 pages, $79.95

Rapid advances in reducing laser pulse duration to the femtosecond range have naturally been accompanied by corresponding advances in time-resolved spectroscopy of semiconductors. J. Shah`s Ultrafast Spectroscopy of Semiconductors and Semiconductor Nanostructures is a treatise on the complex dynamics following ultrashort photoexcitation of compound III-V semiconductors, with an emphasis on gallium arsenide. It is written at a level appropriate for graduate students and researchers in the field of semiconductor spectroscopy and assumes a strong background in solid-state physics.

The introductory chapter begins with a short discussion of band structure in bulk and quantum-well semiconductors, excitons, phonons, and carriers, followed by a description of scattering, carrier relaxation, and carrier transport. Also included are summaries of spectroscopic techniques used in the field as well as a discussion of the interpretation of experimental results. The author refers the reader to the appropriate sources for more details. The remaining seven chapters deal with the dynamics of photo excitation by ultrashort pulses and are organized in order of temporal occurrence following photoexcitation.

Chapter two, "Coherent Spectroscopy of Semiconductors," begins with a theoretical analysis of an independent two-level system tailored to specific optical experiments. The remainder of the chapter deals with the response of the semiconductor immediately following photo-excitation and describes exciton, biexciton, and free-carrier dephasing. Chapter three describes the relaxation from nonthermal to thermal distribution of free carriers, occurring in roughly the same time regime (100 fs) as the coherent effects described in the previous chapter.

Subsequent chapters cover the cooling of the hot electron-hole distributions, phonon dynamics, exciton dynamics, and exciton spin relaxation. The last two chapters explore carrier tunneling and carrier transport in semiconductor nanostructures.

Overall, this book is well organized and clearly written. It provides a complete study of the dynamics of photoexcited III-V compound semiconductor nanostructures and contains numerous references to both basic theory and experimental results. I highly recommend this book to anyone involved in research of photoexcited semiconductor structures.

Peggy Perozzo

Peggy Perozzo is assistant professor, department of physics, Grand Valley State University, 1 Campus Drive, 125 Padnos, Allendale, MI 49401.

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