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No abstract available

[en] The transmission of 500 ns pulses through GaAs-AlGaAs heterostructures has been studied as a function of light intensity and wavelength. The intrinsic exciton absorption can be modeled by the sum of a small unsaturable background and a dominant term which saturates as a Bloch resonance. Corrections for the Gaussian transverse spatial profile and finite optical thickness lead to 150 W/cm² for the uniform-plane-wave saturation intensity for an optically thin GaAs exciton transition. The nearly Bloch-like saturation curve does not imply that the free exciton transition is a simple saturable two-level system, but does suggest that it saturates as a homogeneously broadened line

[en] Single devices and 2-D arrays of bottom-emitting vertical-cavity surface-emitting lasers operating in the 980 nm wavelength regime, have been fabricated for high continuous-wave optical output power. Single devices with active diameters of 500 μm show high output powers of 1.95 W at room temperature. Its threshold current is 510 mA, and the maximum spatially averaged optical power density is 0.93 kW/cm². Arrays consisting of 16 elements of 200 μm active diameters arranged in a square structure achieve output powers of 1.21 W corresponding to a power density of 1 kW/cm² spatially averaged over the effective array chip size. The device threshold current is 1.1 A

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No abstract available

[en] The molecular beam epitaxy is considered to by suitable method for preparation of efficient CaAs solar cells. This paper deals with p/i/n solar cell structures prepared with different thickness of intrinsic i-region. The current-voltage characteristics in the dark and the performance under standard simulated light spectra and concentrated light were investigated.The dielectric properties at the frequency range from 50 Hz to 1 MHz and at different temperatures were investigated, as well. Preliminary results on fully processed 1 cm x 1 cm p/i/n GaAs solar cells have shown an increase in maximum power output by a factor of around 2.7 to 3.0 under concentrated illumination of 5 Suns. This work is being carried out as a part of an effort to fabricate efficient multiple quantum well CaAs cells based on thin film structures. (authors)

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[en] The bibliography contains 77 selected abstracts concerning the operation and performance of gallium arsenide lasers. Included are abstracts on band theory and solid state research as it directly applies to lasing

[en] Deep levels associated with the main impurities such as Cr, O and other defects in semi-insulating GaAs (Cr doped, O doped and undoped) have been measured by thermally stimulated current(TSC) measurements. Deep level energies and capture cross sections are obtained through quasi-fermi level analysis, initial rise, various heating rate and peak shape methods. Samples were annealed at 400 degC, 500 degC, 600 degC, and 700 degC, and from the annealing effects on the deep levels, a possible origin of the deep levels observed in pure GaAs (Bridgeman and LEC) is discussed. (Author)