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Optical properties of semiconductors
BOOKS Very high resolution spectroscopy
Optical properties of semiconductors
Edited by R.A. Smith
Edited by N. G. Basov
Academic Press, 1976, pp 260, $9.80
Plenum, 1976, $52.00
Sub-titles often serve the useful function of making more explicit the aim and content of a book. In this case the title seems sufficient in itself but a closer examination of the book suggests that it might be supplemented by ‘A little bit of not quite everything!’ The book comprises the invited papers presented at the Rank Prize Fund’s recent symposium on ‘Very high resolution spectroscopy’ and a glance at the contents page should underline the significance of this sub-title. The topics range from high resolution infra-red spectroscopy and tunable infra-red lasers, through photon correlation spectroscopy, coherent transient effects and non-linear optical mixing, to photoelectron spectroscopy of molecules. Two articles deal with high resolution in the time domain by ultra-short laser pulses, and to complete the melange there are papers on high resolution astronomy (between 3 pm and 3 mm), spectroscopy within living cells, and computer techniques in spectroscopy.
This volume is a special research report comprising three Russian theses which cover various aspects of optical properties of semiconductors. The original text was published by Nauka Press (Moscow, 1974) for the Academy of Sciences of the USSR, as Volume 75 of the Proceedings of the P.N. Lebedev Physics Institute. It has recently been translated into English by the Consultants Bureau. The protracted time scale of publishing and translating means the work is a little outdated; the theses being successfully defended in 1971 and 1972. However they serve as a useful collection of research details for workers in this field.
Each of the articles treats those sometimes narrow sections of the field of particular interest to the authors, and anyone looking for a comprehensive review of high resolution spectroscopy will not find it here. Indeed some important aspects of the field are not treated at all and at the same time a few of the articles have a rather tenuous connection with the title. For example, the important new technique of saturated absorption spectroscopy is dismissed by one author on the grounds that it is well known and has been reviewed elsewhere. The same comment could be made of much of this book. One wonders if some of the contributors ever tire of rewriting their review papers after each symposium or conference which decides to publish its proceedings. The author list is impressive, including as it does many of the leading research workers from the various fields involved. The contributions are generally readable and do highlight the recent progress that has been made using lasers and associated techniques. However it is unlikely that the book will find much use as a reference text since the articles cover such diverse aspects, and especially since the reference lists for each paper are inadequate. With clear type and beautifully reproduced photographs and diagrams the publishers have produced a well presented book - but at $9.80 for 260 pages, it ought to be.
P.Ewart
OPTICS AND LASER TECHNOLOGY.
OCTOBER
1976
The first section by 1.1. Zasavitskii treats the radiation emitted from semiconductor lasers in strong magnetic fields and under high hydrostatic pressure. The author investigated the properties of injection lasers made from narrow gap semiconductors (InAs, InSb, GaAs, PbSe, PbTe) and demonstrated quasicontinuous output tuning over a relatively wide range (up to 5.4%) by shifting the Landau levels in an applied magnetic field. In the case of PbSe, laser action due to interband transitions of electrons accompanied by spin-flip was observed for the first time. The results yielded values for effective masses and g-factors of carriers near the band edges, and for the widths of the forbidden band. An investigation of the emission from PbSe and GaAs lasers under hydrostatic pressure demonstrated a particularly wide tuning range (tens of percent). He also reports the first observation in the Soviet Union of stimulated spin-flip Raman scattering from conduction electrons in InSb, a tunable infra-red laser. This thesis contains a useful review and summary of energy band parameters in these materials and also contains experimental details of COz lasers, high pressure apparatus, detectors, and superconducting magnets. The other two articles both deal with a topic of current interest to semiconductor physicists, namely the condensation of excitons into electron-hole drops. Even at relatively low exciton concentrations the nature of the interexciton interaction leads to collective effects. Keldysh hypothesized that when the concentration of excitons is increased, a literal condensation should occur. This transition in exciton systems should have many of the characteristic features of phase transitions of the first kind and the resultant regions of dense electron-hole phase should have metallic conduction. In the first of these articles V.A. Zayats measured the far infra-red absorption and luminescence spectra of excited germanium and observed a new resonance at 9 x 10m3eV
235
for a temperature of < 2 K. This is postulated to be due to electron-hole drops. The dipole absorption model was used to determine the plasma frequency and the particle density of these drops. In the final article, L.I. Paduchikh studies the photoluminescence spectra of GaAs and Si under a wide range of optical excitation levels and temperatures. Information was obtained on the photoelectric properties of these semiconductors in the non-equilibrium carrier range, in which the energy band spectrum is again strongly influenced by the collective interaction of electrons and holes. In summary, this book is a useful addition to the library shelves as a detailed reference source on some aspects of Russian work on optical properties of semiconductors. R.B. Dennis
Crystal technology W. L. Bond
‘x-ray data on some crystals’ consisting of 49 pages of tables of Bragg angles for 87 different crystals. The section on ‘Etching’ ends with a short sub-section on ‘BazNaNb501s’ which describes the crystal structure of that substance but does not mention etching it! This is by no means an isolated eccentricity - but it is the most outrageous. The descriptions of apparatus are good but I sometimes found less lucid the explanations of phenomena such as that of Bragg’s law on page 26. Too much is said parenthetically thereby distracting from the development of the main argument. Despite these major criticisms, the book is nevertheless a ‘must’ for those engaged in cutting and polishing because of the authoritative information it contains. Sadly however, the reader will be likely to find it a frustrating book to use and will need to seek information on crystal perfection and damage from other sources. The book is a volume in the Wiley Series in Pure and Applied Optics; perhaps a firm hand from the Series Editor could have transformed it into a lasting handbook. D. T.J. Hurle
John Wiley, 1976, pp 356,215.90 The subject matter of this book, which is much more restricted than the title suggests, covers the orienting, cutting and lapping of single crystals. In addition, there are opening chapters on crystal symmetry, indices, and point and space groups. The text reveals the very extensive technical know-how which the author possesses; from the dust cover of the book one learns that the author was for forty years on the technical staff of Bell Telephone Laboratories. It is in fact a gold-mine of information on jigs and gadgets for cutting and orienting specimens, and is copiously illustrated with clear, uncluttered diagrams. Most of the apparatus described appears to be home-made and, unfortunately, there is virtually no reference to commercially available equipment. Techniques covered include orientation by x-ray and optical techniques, crystal sawing and the grinding of flat, cylindrical, spherical, and toroidal surfaces. The second characteristic of the book is the author’s penchant for coordinate geometry which is used extensively in describing crystallographic relationships and in evaluating the accuracy of various orientation and lapping techniques. Given the, perhaps unrivalled, knowledge and experience of the author in his field, it is disappointing to have to report serious deficiences in the selection and organization of the material. Most serious is the absence of any description of the damage introduced by cutting and polishing and the means by which it can be minimized or removed. Further, although the accuracy to which specimens can be oriented is treated in detail, misorientations and mosaic structure together with more general questions of crystal perfection are not considered. Crystal perfection receives less than half a page sandwiched in a section entitled ‘Identifying strange atomic planes’ - and consists mainly of a brief description of twinning. By contrast, the book contains a lot of, at best, marginally relevant material such as crystal elasticity theory. Also seriously at fault is the organiz.ation of the material presented which really does in places defy all logic. Thus, in a chapter on ‘Materials’ there is a section on ‘Etching’ which, after half a page, opens a sub-section entitled
236
Principles and practice of laser-Doppler anemometry F. Dust,
A. Melling, J. H. Whitelaw
Academic Press, 1976, pp viii + 405,E12.00 Professor Whitelaw and his research school at Imperial College have been notably active for some years in the development of laser Doppler velocimetry techniques for applications to fluid flows, and must be given credit for having played a significant part in stimulating the extensive interest in these techniques which now exists within the fluid mechanics community. A book which embodies the results of their experience and attempts to provide guidance for research workers entering the field is therefore to be welcomed; this volume is also intended to provide students and engineers faced with a specific flow problem with an understanding of the subject of laser anemometry, as well as its practice. The layout of the text clearly reflects its origins in lecture courses, delivered mainly at Imperial College and the University of Karlsruhe in Germany. Each page of chapters 2- 13 is headed by a panel enclosing a summary of the material to be presented, together with relevant illustrations. Although visually attractive, this is a rather constricting form of presentation and is not wellsuited to the development of a lengthy theme (eg light scattering by particles). After a short introductory chapter, which is devoted largely to a historical resume of laser anemometry and the reasons for the interest which it has generated, the physical foundations of the subject are reviewed, including geometrical optics, interference and scattering phenomena, and the basic principles of laser-Doppler instrumentation. This is a very unsatisfactory part of the book; in attempting to compress such a vast and highly developed body of theory into a limited space, a number of loose statements and some basic errors are made. For example on page 34 it is stated that, at an aperture, diverging light beams give rise to
OPTICS AND LASER TECHNOLOGY.
OCTOBER
1976
Optical properties of semiconductors
Edited by R.A. Smith
Edited by N. G. Basov
Academic Press, 1976, pp 260, $9.80
Plenum, 1976, $52.00
Sub-titles often serve the useful function of making more explicit the aim and content of a book. In this case the title seems sufficient in itself but a closer examination of the book suggests that it might be supplemented by ‘A little bit of not quite everything!’ The book comprises the invited papers presented at the Rank Prize Fund’s recent symposium on ‘Very high resolution spectroscopy’ and a glance at the contents page should underline the significance of this sub-title. The topics range from high resolution infra-red spectroscopy and tunable infra-red lasers, through photon correlation spectroscopy, coherent transient effects and non-linear optical mixing, to photoelectron spectroscopy of molecules. Two articles deal with high resolution in the time domain by ultra-short laser pulses, and to complete the melange there are papers on high resolution astronomy (between 3 pm and 3 mm), spectroscopy within living cells, and computer techniques in spectroscopy.
This volume is a special research report comprising three Russian theses which cover various aspects of optical properties of semiconductors. The original text was published by Nauka Press (Moscow, 1974) for the Academy of Sciences of the USSR, as Volume 75 of the Proceedings of the P.N. Lebedev Physics Institute. It has recently been translated into English by the Consultants Bureau. The protracted time scale of publishing and translating means the work is a little outdated; the theses being successfully defended in 1971 and 1972. However they serve as a useful collection of research details for workers in this field.
Each of the articles treats those sometimes narrow sections of the field of particular interest to the authors, and anyone looking for a comprehensive review of high resolution spectroscopy will not find it here. Indeed some important aspects of the field are not treated at all and at the same time a few of the articles have a rather tenuous connection with the title. For example, the important new technique of saturated absorption spectroscopy is dismissed by one author on the grounds that it is well known and has been reviewed elsewhere. The same comment could be made of much of this book. One wonders if some of the contributors ever tire of rewriting their review papers after each symposium or conference which decides to publish its proceedings. The author list is impressive, including as it does many of the leading research workers from the various fields involved. The contributions are generally readable and do highlight the recent progress that has been made using lasers and associated techniques. However it is unlikely that the book will find much use as a reference text since the articles cover such diverse aspects, and especially since the reference lists for each paper are inadequate. With clear type and beautifully reproduced photographs and diagrams the publishers have produced a well presented book - but at $9.80 for 260 pages, it ought to be.
P.Ewart
OPTICS AND LASER TECHNOLOGY.
OCTOBER
1976
The first section by 1.1. Zasavitskii treats the radiation emitted from semiconductor lasers in strong magnetic fields and under high hydrostatic pressure. The author investigated the properties of injection lasers made from narrow gap semiconductors (InAs, InSb, GaAs, PbSe, PbTe) and demonstrated quasicontinuous output tuning over a relatively wide range (up to 5.4%) by shifting the Landau levels in an applied magnetic field. In the case of PbSe, laser action due to interband transitions of electrons accompanied by spin-flip was observed for the first time. The results yielded values for effective masses and g-factors of carriers near the band edges, and for the widths of the forbidden band. An investigation of the emission from PbSe and GaAs lasers under hydrostatic pressure demonstrated a particularly wide tuning range (tens of percent). He also reports the first observation in the Soviet Union of stimulated spin-flip Raman scattering from conduction electrons in InSb, a tunable infra-red laser. This thesis contains a useful review and summary of energy band parameters in these materials and also contains experimental details of COz lasers, high pressure apparatus, detectors, and superconducting magnets. The other two articles both deal with a topic of current interest to semiconductor physicists, namely the condensation of excitons into electron-hole drops. Even at relatively low exciton concentrations the nature of the interexciton interaction leads to collective effects. Keldysh hypothesized that when the concentration of excitons is increased, a literal condensation should occur. This transition in exciton systems should have many of the characteristic features of phase transitions of the first kind and the resultant regions of dense electron-hole phase should have metallic conduction. In the first of these articles V.A. Zayats measured the far infra-red absorption and luminescence spectra of excited germanium and observed a new resonance at 9 x 10m3eV
235
for a temperature of < 2 K. This is postulated to be due to electron-hole drops. The dipole absorption model was used to determine the plasma frequency and the particle density of these drops. In the final article, L.I. Paduchikh studies the photoluminescence spectra of GaAs and Si under a wide range of optical excitation levels and temperatures. Information was obtained on the photoelectric properties of these semiconductors in the non-equilibrium carrier range, in which the energy band spectrum is again strongly influenced by the collective interaction of electrons and holes. In summary, this book is a useful addition to the library shelves as a detailed reference source on some aspects of Russian work on optical properties of semiconductors. R.B. Dennis
Crystal technology W. L. Bond
‘x-ray data on some crystals’ consisting of 49 pages of tables of Bragg angles for 87 different crystals. The section on ‘Etching’ ends with a short sub-section on ‘BazNaNb501s’ which describes the crystal structure of that substance but does not mention etching it! This is by no means an isolated eccentricity - but it is the most outrageous. The descriptions of apparatus are good but I sometimes found less lucid the explanations of phenomena such as that of Bragg’s law on page 26. Too much is said parenthetically thereby distracting from the development of the main argument. Despite these major criticisms, the book is nevertheless a ‘must’ for those engaged in cutting and polishing because of the authoritative information it contains. Sadly however, the reader will be likely to find it a frustrating book to use and will need to seek information on crystal perfection and damage from other sources. The book is a volume in the Wiley Series in Pure and Applied Optics; perhaps a firm hand from the Series Editor could have transformed it into a lasting handbook. D. T.J. Hurle
John Wiley, 1976, pp 356,215.90 The subject matter of this book, which is much more restricted than the title suggests, covers the orienting, cutting and lapping of single crystals. In addition, there are opening chapters on crystal symmetry, indices, and point and space groups. The text reveals the very extensive technical know-how which the author possesses; from the dust cover of the book one learns that the author was for forty years on the technical staff of Bell Telephone Laboratories. It is in fact a gold-mine of information on jigs and gadgets for cutting and orienting specimens, and is copiously illustrated with clear, uncluttered diagrams. Most of the apparatus described appears to be home-made and, unfortunately, there is virtually no reference to commercially available equipment. Techniques covered include orientation by x-ray and optical techniques, crystal sawing and the grinding of flat, cylindrical, spherical, and toroidal surfaces. The second characteristic of the book is the author’s penchant for coordinate geometry which is used extensively in describing crystallographic relationships and in evaluating the accuracy of various orientation and lapping techniques. Given the, perhaps unrivalled, knowledge and experience of the author in his field, it is disappointing to have to report serious deficiences in the selection and organization of the material. Most serious is the absence of any description of the damage introduced by cutting and polishing and the means by which it can be minimized or removed. Further, although the accuracy to which specimens can be oriented is treated in detail, misorientations and mosaic structure together with more general questions of crystal perfection are not considered. Crystal perfection receives less than half a page sandwiched in a section entitled ‘Identifying strange atomic planes’ - and consists mainly of a brief description of twinning. By contrast, the book contains a lot of, at best, marginally relevant material such as crystal elasticity theory. Also seriously at fault is the organiz.ation of the material presented which really does in places defy all logic. Thus, in a chapter on ‘Materials’ there is a section on ‘Etching’ which, after half a page, opens a sub-section entitled
236
Principles and practice of laser-Doppler anemometry F. Dust,
A. Melling, J. H. Whitelaw
Academic Press, 1976, pp viii + 405,E12.00 Professor Whitelaw and his research school at Imperial College have been notably active for some years in the development of laser Doppler velocimetry techniques for applications to fluid flows, and must be given credit for having played a significant part in stimulating the extensive interest in these techniques which now exists within the fluid mechanics community. A book which embodies the results of their experience and attempts to provide guidance for research workers entering the field is therefore to be welcomed; this volume is also intended to provide students and engineers faced with a specific flow problem with an understanding of the subject of laser anemometry, as well as its practice. The layout of the text clearly reflects its origins in lecture courses, delivered mainly at Imperial College and the University of Karlsruhe in Germany. Each page of chapters 2- 13 is headed by a panel enclosing a summary of the material to be presented, together with relevant illustrations. Although visually attractive, this is a rather constricting form of presentation and is not wellsuited to the development of a lengthy theme (eg light scattering by particles). After a short introductory chapter, which is devoted largely to a historical resume of laser anemometry and the reasons for the interest which it has generated, the physical foundations of the subject are reviewed, including geometrical optics, interference and scattering phenomena, and the basic principles of laser-Doppler instrumentation. This is a very unsatisfactory part of the book; in attempting to compress such a vast and highly developed body of theory into a limited space, a number of loose statements and some basic errors are made. For example on page 34 it is stated that, at an aperture, diverging light beams give rise to
OPTICS AND LASER TECHNOLOGY.
OCTOBER
1976