In this paper we investigate the current density due to electrons emitted during normal irradiation of a toroidal quantum ring of a strongly degenerate wide-gap semiconductor. The computed results show that the current density increases in a step-like manner with increase in the incident photon energy. Increased current density can be obtained by reducing the dimensions of the ring. The threshold energy for photoemission becomes an oscillatory function of the cross-sectional radius, and can be used as an important tool for monitoring parameters such as the cross-sectional radius and doping density. The threshold energy is, however, independent of the circumference of the ring.

An attempt is made to investigate the effects of an oriented magnetic field on the field emission from quantum wells in ultrathin films of wide-gap semiconductors taking n-type GaAs as an example. The field emission current density is found to increase both with increasing electric field and with increasing film thickness. Furthermore, the emission shows an oscillatory nature with a quantizing magnetic field, its orientation, and the film thickness. At a given value of the magnetic field, the oscillatory nature is most significantly influenced by the effects of size quantization at relatively small values of the film thickness.

A transverse perturbing magnetic field is assumed to be applied to a rectangular quantum wire of a wide-gap semiconductor, to determine the magnetic susceptibilities of electrons. The computations are performed for a low value of the temperature, taking degenerate n-GaAs as an example of such semiconductors. It is interesting to note that, not only the paramagnetic-to-diamagnetic susceptibility ratio for electrons in a semiconducting quantum wire deviates from that (1/3) in conventional semiconductors, but also that there is a critical region, governed by the concentration of the electrons and the transverse dimensions of the wire within which quenching of the diamagnetism occurs.

An attempt is made to investigate the electric field-aided photoemission from quantum wells in ultrathin films of degenerate wide-gap semiconductors, taking n-type GaAs as an example. It is found that the photoemission varies in a step-like manner with photon energies close to the electron affinity and exhibits oscillatory character in its dependence on the film thickness, both in presence and absence of an electric field. For photon energies significantly lower than the electron affinity, a quantized nature of the emission is observed in certain ranges of film thicknesses. Besides, the rate of increase of the photoemission with electric field is seen to increase with increasing film thickness over the range of thicknesses of interest in ultrathin films.

physica status solidi (b)Volume 170, Issue 2 p. K115-K119 Short Note On Quantized Photoemission from a Cylindrical Quantum Box of a Wide-Gap Semiconductor N. R. Das, N. R. Das Institute of Radio Physics and Electronics, University College of Science and Technology, Calcutta Search for more papers by this authorA. N. Chakravarti, A. N. Chakravarti Institute of Radio Physics and Electronics, University College of Science and Technology, Calcutta Search for more papers by this author N. R. Das, N. R. Das Institute of Radio Physics and Electronics, University College of Science and Technology, Calcutta Search for more papers by this authorA. N. Chakravarti, A. N. Chakravarti Institute of Radio Physics and Electronics, University College of Science and Technology, Calcutta Search for more papers by this author First published: 1 April 1992 https://doi.org/10.1002/pssb.2221700242Citations: 2 92, Acharya P.C. Road, Calcutta 700 009, India. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume170, Issue21 April 1992Pages K115-K119 RelatedInformation

A perturbational approach is used to investigate the effect of a tilted magnetic field on the energy eigenvalues and the diffusivity-mobility ratio (the Einstein relation) of the electrons in a quantum wire (a quasi-one-dimensional structure) of an n-type wide-gap semiconductor having a rectangular cross-section. The results computed corresponding to the temperature 4.2 K are presented, taking degenerate n-GaAs as an example.

A perturbational calculation is presented for determining the energy eigenvalues of the confined electrons in a cylindrical quantum box of a wide-gap n-type semiconductor in the presence of crossed electric and magnetic fields. Besides, the effects of changing the fields as well as the radius and the width of the box on the lowest quantized state in such a structure are investigated, taking n-type GaAs as an example.

The energy eigenvalues of the electrons in a quantum box of a simple Kane-type narrow-gap semiconductor having cylindrical symmetry are investigated through a perturbation technique in the presence of crossed electric and magnetic fields. The effects of changing the dimensions of the box as also of changing the fields on the lowest quantized state are discussed using the relations obtained, taking n-InSb as a typical example of such a semiconductor.

An attempt is made to investigate the diamagnetic and paramagnetic susceptibilities of electrons in a quantum box of an n-type wide-gap semiconductor by considering perturbational effects of an external magnetic field. The results are computed for quantum cubes, taking n-GaAs as an example. The susceptibilities are found to be oscillatory in nature because of the quantum size effect, while the ratio of the susceptibilities is observed to deviate significantly from the value well-known for bulk semiconductors.

AbstractAn attempt is made to investigate the quantized photoemission from the magneto‐size‐quantized levels of quantum wells in ultrathin films of wide‐gap semiconductors in the presence of an electric field, taking n‐type GaAs as an example. It is found that the photocurrent changes with photon energy in a step‐like manner in which the number of steps increases for relatively large film thicknesses with consequent decrease of the step heights at given values of the electric and magnetic fields. Besides, it is seen that the photoemission becomes quantized for photon energies significantly lower than the electron affinity whereas it becomes oscillatory as the electron affinity is approached. The effects of continuous variation of either the electric or the magnetic field on the photocurrent corresponding to different film thicknesses are also discussed.

AbstractAn attempt is made to investigate the effects of a tilted magnetic field on the size‐quantized levels of quantum wells in ultrathin films of narrow‐gap semiconductors, taking n‐type InSb as an example. It is found that, in general, the energy eigenvalue of the lowest magneto‐size‐quantized level increases with increasing magnetic field and decreases both, with increasing film thickness and with increasing orientation of the magnetic field, for given values of the other parameters. Besides, it is observed that the difference of the energy eigenvalues of the lowest two magnetic sub‐levels of the lowest electric sub‐band reaches a maximum at a given magnetic field, showing a decrease with its orientation, while it increases with the film thickness.

An attempt is made to investigate the effects of a tilted magnetic field on the size-quantized levels of quantum wells in ultrathin films of wide-gap semiconductors, taking n-GaAs as an example. It is found that the energy eigenvalue of the lowest Landau level corresponding to a given electric subband increases with increasing magnetic field, and reaches a maximum corresponding to a given orientation of the field, the dependence being increasingly prominent with increasing size quantum numbers. Besides, the eigenvalue corresponding to the lowest electric subband decreases with increasing film thickness, the rate of decrease being significantly dependent on the magnetic field and its orientation. Der Einflus eines geneigten Magnetfeldes auf die gequantelten Niveaus in ultradunnen Filmen von Halbleitern mit breiter Bandlucke wird am Beispiel des n-GaAs untersucht. Es wird gefunden, das die Energie-Eigenwerte des tiefsten Landau-Niveaus fur ein gegebenes elektrisches Sub-Band mit der magnetischen Feldstarke wachsen und ein Maximum erreichen (fur feste Feldrichtung), wobei die Abhangigkeit mit wachsender Quantenzahl ausgepragter wird. Uberdies nimmt der Eigenwert des tiefsten Subbands mit wachsender Filmdicke ab, wobei die Rate der Abnahme signifikant von Starke und Richtung des Magnetfeldes abhangen.

AbstractAn attempt is made to study the dependence of the Einstein relation on carrier concentration in heavily doped compensated semiconductors with broadened tail states, both in the presence and absence of a quantizing magnetic field, taking n‐InSb as an example. It is found that, corresponding to a given free electron concentration, the broadening of the tail states modifies the Einstein relation by enhancing the diffusivity–mobility ratio in the absence of magnetic quantization while the reverse is observed in the presence of a quantizing magnetic field. Besides, the rate of decrease of the ratio with increasing magnetic field in the quantum limit is found to be independent of such broadening effects.

AbstractAn attempt is made to investigate the effects of a tilted quantizing magnetic field on the photoemission from quantum wells in ultrathin films of wide‐gap semiconductors, taking n‐type GaAs as an example. The photoemission exhibits an increasing step‐like variation with increasing photon energy and is also found to have oscillatory dependence on the magnetic field, its orientation, and the film thickness. Strikingly, the dependence of the emission on film thickness, for photon energies considerably lower than the electron affinity, shows that it gets quantized.

physica status solidi (b)Volume 144, Issue 1 p. K13-K18 Short Note Quantized Photoemission from Quasi-Two-Dimensional Structures of Wide-Gap Semiconductors in a Strong Magnetic Field C. Majumdar, C. Majumdar Institute of Radio Physics and Electronics, University College of Science and Technology, Calcutta Search for more papers by this authorA. B. Maity, A. B. Maity Institute of Radio Physics and Electronics, University College of Science and Technology, Calcutta Search for more papers by this authorA. N. Chakravarti, A. N. Chakravarti Institute of Radio Physics and Electronics, University College of Science and Technology, Calcutta Search for more papers by this author C. Majumdar, C. Majumdar Institute of Radio Physics and Electronics, University College of Science and Technology, Calcutta Search for more papers by this authorA. B. Maity, A. B. Maity Institute of Radio Physics and Electronics, University College of Science and Technology, Calcutta Search for more papers by this authorA. N. Chakravarti, A. N. Chakravarti Institute of Radio Physics and Electronics, University College of Science and Technology, Calcutta Search for more papers by this author First published: 1 November 1987 https://doi.org/10.1002/pssb.2221440141Citations: 9 92, Acharya Prafulla Chandra Road, Calcutta 700009, India. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume144, Issue11 November 1987Pages K13-K18 RelatedInformation

AbstractAn attempt is made to investigate the effects of size quantization on field emission from ultrathin films of degenerate wide‐gap semiconductors, taking the image force into consideration. It is noted, taking n‐type GaAs as an example, that size quantization enhances the field emission by several orders of magnitude as compared to that of bulk specimens. Such quantization also leads to oscillatory behavior of the emission with changing film thickness and to a significant dependence of the emission on field strength and carrier concentration.

physica status solidi (b)Volume 141, Issue 1 p. K35-K40 Short Note On the Photoemission from Quasi-One-Dimensional Structures of Wide-Gap Semiconductors Having Rectangular Cross-Sections C. Majumdar, C. Majumdar Institute of Radio Physics and Electronics, University College of Science and Technology, Calcutta Search for more papers by this authorA. B. Maity, A. B. Maity Institute of Radio Physics and Electronics, University College of Science and Technology, Calcutta Search for more papers by this authorA. N. Chakravarti, A. N. Chakravarti Institute of Radio Physics and Electronics, University College of Science and Technology, Calcutta Search for more papers by this author C. Majumdar, C. Majumdar Institute of Radio Physics and Electronics, University College of Science and Technology, Calcutta Search for more papers by this authorA. B. Maity, A. B. Maity Institute of Radio Physics and Electronics, University College of Science and Technology, Calcutta Search for more papers by this authorA. N. Chakravarti, A. N. Chakravarti Institute of Radio Physics and Electronics, University College of Science and Technology, Calcutta Search for more papers by this author First published: 1 May 1987 https://doi.org/10.1002/pssb.2221410143Citations: 11 92, Acharya Prafulla Chandra Road, Calcutta 700009, India. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL References 1 R. Dingle, Festkörperprobleme, Vol. 15, Pergamon Press/Vieweg, 1975 and references cited therein. 2 L. L. Chang and K. Ploog, Molecular Beam Epitaxy and Heterostructures, Martinus, Nijhoff Publishers, 1985. 3 T. Andorsan, A. B. Fowler, and F. Stern, Rev. mod. Phys. 54, 437 (1982) and references cited therein. 4 V. K. Arora, J. Phys. C 28, 3011 (1985). 5 H. Sakaki, Japan. J. appl. Phys. 19, L735 (1980). 6 H. Sakaki, J. Vacuum Sci. Technol. 19, 198 (1981). 7 P. M. Petroeff, A. C. Gossard, R. A. Logan, and W. Wiegmann, Appl. Phys. Letters 41, 635 (1982). 8 A. Van der Ziel, Solid State Physical Electronics, Prentice-Hall, New York 1957. 9 J. S. Blakemore, Semiconductor Statistics, Pergamon Press, London 1962. 10 R. K. Pathria, Statistical Mechanics, Pergamon Press, Oxford 1972. Citing Literature Volume141, Issue11 May 1987Pages K35-K40 ReferencesRelatedInformation

AbstractAn attempt is made to investigate the effects of size quantization on the field emission from ultrathin films of degenerate wide‐gap semiconductors. It is found, taking n‐type GaAs as an example, that the presence of size quantization increases the field emission by several orders of magnitude as compared to that from bulk specimens of the same semiconductor. Under such quantization, the field emission may also show oscillatory behavior with decreasing film thickness, and is further found to be strongly dependent on the field strength and the carrier concentration.

AbstractAn attempt is made to investigate the effects of varying the orientation of a quantizing magnetic field on the effective mass in tetragonal semiconductors. It is found, taking n‐Cd3As2 as an example, that the crystal‐field splitting results in different effective masses at the Fermi level corresponding to different magnetic sub‐bands. These effective masses are found to be significantly influenced by the orientation of the magnetic field with respect to the c‐axis. This behaviour is further noted to be strongly dependent on the carrier concentration but is relatively much less sensitive to changes in the magnetic field strength.

AbstractAn attempt is made to formulate the generalized carrier statistics in superlattice structures of small‐gap semiconductors by deriving expressions for the density‐of‐states function and the carrier concentration in such structures in the presence of a quantizing magnetic field. The corresponding expressions for superlattices of large‐gap semiconductors can easily be obtained from the generalized relations derived. These results would be more general than those reported in the literature for such structures of large‐gap semiconductors on the basis of tight‐binding approximations.