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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 91 (2002), S. 5875-5881 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: InGaAs strained quantum well (SQW) samples with lattice matched InGaAsP quaternary barriers are grown on GaAs substrates by metalorganic vapor phase epitaxy. These SQW samples are characterized using photoluminescence, photomodulated reflectance, surface photovoltage spectroscopy and high-resolution x-ray diffraction techniques. The results based on numerical calculations are used to identify the various transitions seen in the spectra. The effect of growth temperature on the indium content of the InGaAs SQW with lattice matched InGaAsP quaternary barriers is studied. Contrary to the reported higher value of indium incorporation in InGaAs SQW with GaAs (In-free) barriers when the growth is performed at low temperatures, we find that the indium content of the InGaAs SQW with InGaAsP (In-based) quaternary barriers decreases if the SQW is grown at lower growth temperatures. A possible explanation for this behavior is provided. © 2002 American Institute of Physics.
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 73 (2002), S. 1835-1840 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A procedure for choosing the appropriate chopping frequency (f) for the surface photovoltage spectroscopy (SPS) measurements in order to obtain the absorption related features is presented. We could obtain the absorption edge of thick n+ GaAs wafer (thickness (approximate)700 μm) by performing SPS measurements at f≥1 kHz at room temperature (300 K). The similar information for semi-insulating (SI) GaAs could not be obtained due to the carrier trapping at deep levels or surface states at 300 K. However, we could obtain the absorption edge of SI-GaAs by performing SPS measurements at 395 K at f=3 kHz. Here, we demonstrate the capability of the SPS technique to measure large absorption coefficient (α) values for thick wafers by performing SPS measurements and normalizing this with the reported α value at one wavelength in the above band gap region. For comparison, we also perform quasisimultaneous SPS and transmission spectroscopy (TS) measurements. The SPS technique could provide α values up to 104 cm−1 for 700-μm-thick GaAs wafers, whereas TS could only measure α values up to about 15 cm−1. An improved design of the sample holder for measuring the surface photovoltage in the chopped light geometry, which increases the signal strength by reducing the gap between the top electrode and the wafer in a controlled manner, is presented. This ensures that there is no sample damage or contamination. © 2002 American Institute of Physics.
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  • 3
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report the observation of strongly polarization sensitive sub-band gap oscillatory features in the contactless electroreflectance spectrum of InxGa1−xP layers grown on GaAs (001) substrates. At a given energy in the sub-band gap region, the peak strength of these oscillatory features decreases from a positive maximum to a negative minimum passing through zero as the polarization of the incident probe beam is rotated by 90° from [11¯0] direction to [110] direction in the (001) plane. The origin of this phenomenon is explained on the basis of optical interference coupled with linear electro-optic effect induced changes in the sub-band gap refractive index of the InxGa1−xP layers. Numerical simulations based on the above mechanism are shown to reproduce the polarization dependent observations quite well. © 1998 American Institute of Physics.
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  • 4
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 79 (2001), S. 1715-1717 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Surface photovoltage spectroscopy (SPS) studies on thick semi-insulating (SI) GaAs wafers have been done in the range 800–1100 nm using chopped light geometry. SPS peaks at 880 nm, 900 nm, and a broadband in the range 930–1080 nm have been observed. These observations are important as SPS is routinely used to study absorption-related features in InAs self-organized quantum dots grown on SI GaAs. The effect of the ambient and chopping frequencies on SPS spectra is also presented. © 2001 American Institute of Physics.
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  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 57 (1985), S. 2973-2974 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The theoretical calculations for the diode quality factor n for a metal-insulator-n-semiconductor solar cell under illumination are presented here. These calculations show that, under illumination, n increases with increasing d and decreases slightly for d〉18 A(ring) at JL =36 mA cm−2. Results of the calculations compare well with experimental results observed by H. C. Card [Solid-State Electron. 20, 971 (1977)].
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 44 (1979), S. 0 
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Accuracy and suitability of various wavelengths employing reflectance spectrophotometry for measuring K/S ratios or RA values, was critically analysed for the estimation of fresh mutton color. The K/S ratio method using wavelengths 572 and 525 nm gave more consistent results than other wavelengths. The lower myoglobin content of mutton as compared to that of beef was, however, responsible for narrower ranges obtained for differentiation of fresh and oxidized mutton color. The commercial acceptability limit for fresh mutton color was 0.09 units less than the initial value of K/S 572/525 ratio.
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  • 7
    Electronic Resource
    Electronic Resource
    Cambridge : Cambridge University Press
    Modern Asian studies 10 (1976), S. 349-360 
    ISSN: 0026-749X
    Source: Cambridge Journals Digital Archives
    Topics: Ethnic Sciences , History , Political Science , Economics
    Notes: At the moment, India, with two Congress Parties, two Jana Sanghs, two Socialist Parties, two D.M.K.s, two Akali Dals and two Communist Parties (the third Communist Party—the C.P.M.L.—has been declared illegal after the present emergency), presents a picture with ‘splitism’ as the common denominator. The split in the Communist Party of India occurred at a time when the Communist movement all over the world was in disarray, showing polycentric trends on account of Sino-Soviet polemics. In addition to this, the Sino-Indian border war of 1962 also put serious strain on the party unity. Therefore, most of the studies that were undertaken on the C.P.I, split ascribed it either to the Sino-Soviet schism or to the Sino-Indian border war, or to both. However, an analysis of the authoritative pronouncements of two factions and an examination of their political resolutions indicate sharp differences on such issues as the character of the Congress Party, the nature of its government and the progressive and reactionary contents of its economic, home and foreign policy. The rightsts in the C.P.I, considered the national bourgeoisie Congress Party and its government as a progressive force and consequently advocated a policy of ‘Unity’ with it, in its fight against the parties of the Right reaction, such as the Jana Sangh, the Swatantra and the two variants of the Socialist Party.
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  • 8
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Experimental Cell Research 87 (1974), S. 394-397 
    ISSN: 0014-4827
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Journal of Inorganic and Nuclear Chemistry 37 (1975), S. 1845-1849 
    ISSN: 0022-1902
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    International Journal of Mass Spectrometry and Ion Physics 4 (1970), S. 69-74 
    ISSN: 0020-7381
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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