Book Review: GaAs High-Speed Devices — Physics, Technology, and Circuit Applications: C. Y. CHANG and FRANCIS KAI

technology? This book steers a pleasant middle way between these two disciplines, presenting the physics in a way which should encourage engineers, and it does not delve too far into electronic principles, which sometimes deters physics students from taking the interest which the subject should demand from them. The first seven chapters deal with the subject matter which is the basis of all optoelectronics courses, namely semiconductor crystalline and electrical properties, p-n junction behaviour, lightemitting diodes, lasers, photoconductors, p-i-n diodes, and avalanche photodiodes. This section takes up 380 of the total 550 pages. The final three chapters then depart somewhat from other texts, to cover areas which overlap science and engineering and should be of interest to both, such as manufacture and growth of materials, technology of fabrication, and the crucial area of packaging and testing. Such topics might persuade some 'scientists' to take an interest in these areas. The text is well written and clearly printed, as are the many diagrams and illustrations, albeit in black and white only, but the clarity of drawing is such that colours are not needed. The layout, in typical British fashion, does not leave wide margins available for writing in additional notes by students, although space is available on many pages due to the presence of the figures. Worked examples are included at appropriate places within each chapter, and there are problems at the ends of-the chapters, but, unfortunately, no answers to allow students to check their efforts. A most useful feature is the extensive list of references which follows each chapter, and which allows students to pursue their interest to whatever extent they wish. The overall level of the text makes it useful for both second and third year honours degree courses for physicists, electronic engineers, and materials scientists, and also for some students of manufacturing technolgoy. JOHN A. SHAW Division of Physics, University of Hertfordshire