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Two-color InGaN/GaN micro-facet multiple-quantum well (MQW) samples grown on 4 in. Si (111) substrate were systematically characterized. The micro-facet structure was achieved by epitaxial lateral overgrowth on SiO2 masked GaN surfaces with stripes along the <[formula]> direction and composed of (0001) and ([formula]) facets. Two different emission peaks stemming from (0001) and ([formula]) oriented MQWs are observed by photoluminescence. The relative intensities of the two peaks can be tuned by controlling the structure's geometry and the experimentally derived growth rates on the different facets. For each facet, we have also determined the MQWs' optical properties, the polarization, the internal quantum efficiency, and the light extraction efficiency. In addition, we analyzed the blue shift for differently oriented MQWs as function of temperature and excitation power. [ABSTRACT FROM AUTHOR]

Focuses on strained single quantum wells composed of gallium arsenide (GaAs)/indium-gallium-arsenic (InGaAs)/GaAs grown by molecular beam epitaxy. Application of photoreflectance by photoluminescence spectroscopy; Empirical equation describing the nonstrained band-gap energy function; Optical properties of the InGaAs/GaAs system.

Presents a study that investigated the growth, structural, electrical and optical characterization of strained triple-quantum-well light emitting diodes. Use of molecular beam epitaxy to grow the heterostructures; Optical performance of the diodes.

Presents information on a study which investigated optical transitions in quantum-well heterostructures revealed by photomodulated absorption (PA) spectroscopy. Growth of the samples by molecular beam epitaxy on undoped gallium arsenide (GaAs) substrates; Nonmodulated absorption measurements on the double-barrier heterostructure; Application of the PA technique to a thick In[sub0.04]Ga[sub0.96]Aslayer on a GaAs substrate.

Presents a study which utilized photoluminescence and magneto-luminescence techniques to evaluate the optical properties of pseudomorphic arsenides modulation doped single quantum wells. Analysis of the data using self-consistent calculations; Relation of coupling effects on transitions in the emission spectra.

Describes the fabrication of cross-shaped Hall sensors with high sensitivity and excellent temperature stability from quantum wells based on an InAS/Al[sub 0.2]Ga[sub 0.8]Sb heterostructure. Epitaxial growth and device fabrication; Temperature dependence of the input resistance for all three sensors.

Photoreflectance spectra have been used to characterize miniband formation in GaAs/ Alx Ga1-x As superlattices with wide wells (275–255 Å) and withb arriers as thin as 17 Å. Thirty-two optical transitions are resolved in the photoreflectance spectra of the 17 Å barrier sample. These experimental transitions match all those theoretically predicted from the selection rule Δn=0, including Γ- and Π-type transitions arising from miniband dispersion; these results imply sample perfection. A sample with a 40 Å barrier exhibits forbidden transitions with Δn≠0; these additional transitions, together with the narrow width of the minibands for 40 Å barriers, create difficulty in resolving the miniband structure. [ABSTRACT FROM AUTHOR]

Modulation-doped In[sub 0.5]Ga[sub 0.5]As/In[sub 0.5]Al[sub 0.5]As quantum well structures grown by molecular beam epitaxy on GaAs substrates using a relaxed AlGaAsSb buffer showed carrier mobilities of 8500 cm[sup 2]/V s for a sheet concentration of 3.5×10[sup 12] cm[sup -2] at room temperature. The crystallinity of the quaternary buffer layer was verified by x-ray diffractometry. Transistors with 0.25×100 μm[sup 2] gates demonstrated transconductance values as high as 800 mS/mm. S-parameter measurements revealed a cutoff frequency f[sub T] of 87 GHz and a maximum oscillation frequency f[sub MAX] of 140 GHz (both extrinsic values). © 1998 American Institute of Physics. [ABSTRACT FROM AUTHOR]