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Investigates the properties of gallium arsenide and aluminum gallium arsenide quantum well heterostructures using transmission electron microscopy together with photoluminescence. Description of modifications to the reactor; Element used to characterize heterostructures; Factor used to qualitatively determine the structural quality of the quantum well.

The growth of GaInP/AlGaAs heterostructures by organometallic vapor phase epitaxy is reported. It was observed that different GaInP alloy compositions are required to lattice match films to AlGaAs and GaAs buffer layers for optimum results. Quantum well heterostructures with GaInP regions as narrow as 30 Å have been produced with abrupt transitions of the group III and group V species across each interface. The results suggest that this material system is suitable for the fabrication of high efficiency visible light sources. [ABSTRACT FROM AUTHOR]

The growth of AlGaAs/GaAs heterostructures by low pressure organometallic vapor phase epitaxy was studied using Raman spectroscopy on a series of multilayer structures. Growth conditions were chosen to allow the investigation of the effects of growth rate and growth interruption during the formation of each type of interface (aluminum "turn on" and "turn off"). This study represents the first report on the use of Raman for the quantitative measurement of the alloy composition in each region ora superlattice structure, where the observation is made that an extended growth interruption is required for the growth of thin GaAs regions (less than 100 Å) over AlGaAs (Al "turn off") while the other interface requires no growth interruption. [ABSTRACT FROM AUTHOR]

High external power efficiencies of 36% are obtained from 5-μm mesa isolated graded-index separate-confinement heterostructure single quantum well lasers grown by organometallic vapor phase epitaxy. Threshold currents of 21 mA are reported for a 5×96 μm cavity laser with differential quantum efficiencies of as high as 80% at 6 mW/facet. In addition, high facet power densities of 13 mW/μm are reported giving single ended output powers of 65 mW from 5-μm uncoated facets. Even higher power densities of 20 mW/μm are observed for 1-μm mesa stripe lasers before probe damage occurred. [ABSTRACT FROM AUTHOR]

The geometry of quantum well surface-emitting lasers has several important consequences. The ultrashort (∼1 μm) vertical cavity defines longitudinal modes with energy separation greater than the bandwidth of spectral gain. The optical confinement of these modes can approach unity. To achieve lasing, high carrier densities (∼1012 cm-2) in the quantum well are required. The confined carriers interact through enhanced many-body exchange which influences both the lasing wavelength and threshold characteristics. Indeed, the exchange interaction can facilitate the lasing process. We theoretically and experimentally study the role of the short cavity and exchange interaction on the cw lasing threshold as a function of temperature. In constrast to edge emitters, the lasing threshold in these surface emitters exhibits a well-defined minimum at a particular temperature. The temperature of the minimum can be designed by merely changing the active layer thickness. [ABSTRACT FROM AUTHOR]

A novel surface-emitting semiconductor laser with a vertical resonator, extremely short gain length, and enhanced gain at a specific design wavelength has been demonstrated. The gain medium consists of a series of GaAs quantum wells separated by AlGaAs spacers whose thicknesses are chosen to be one-half the wavelength of a particular transition in the quantum wells. This structure forces the antinodes of the standing-wave optical field to coincide with the gain elements, enhancing the gain and frequency selectivity in the vertical direction and substantially reducing amplified spontaneous emission. We have achieved optically pumped lasing with a threshold of 6 MW/cm2 at room temperature in a molecular beam epitaxially grown structure of thickness 4.3 μm, of which only 320 nm provided gain. [ABSTRACT FROM AUTHOR]