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Presents a study which showed evidence indicating asymmetry in the shapes of as-grown symmetric coupled double gallium arsenide and AlGaAs quantum wells (CDQW) which were modified by capping with silicon dioxide followed by thermal annealing. Details on studies of the modification of semiconductor quantum well shapes; Materials and methods used; Description of photoluminescence spectra of CDQW wafer.

Presents a study that assessed the effect of shallow ion implantation and rapid thermal annealing on the interdiffusion of gallium and aluminum atoms at aluminum gallium arsenide (GaAs)/GaAs heterointerfaces in a variety of structures as a function of quantum well (QW) width. Background on QW structures; Analysis of the dependence of the photoluminescence energy shifts on QW width; Examination of the uniformity of the interdiffusion.

Presents a study which utilized electroreflectance spectroscopy to investigate a GaAs/Ga[sub0.77]Al[sub0.23]As coupled double quantum well (CDQW) system as a function of externally applied electric field. Detection of intra- and inter-well exciton transitions; Lineshape consideration for modulated reflectivity; Effects of electric fields on CDQW.

Presents a study which reported the effect of furnance annealing on InGaAs/GaAs quantum wells in the range of indium composition. Observation on the changes as a result of annealing, manifested by strain recovery; Importance of the stability of strained layers subjected to heat treatment for device applications.

Focuses on the use of magnetophotoluminescence excitation spectroscopy to study GaAs-AlGasAs coupled double quantum wells. Technique used to measure the hole Landau levels; Photoluminescence excitation spectrum at zero magnetic field; Effects of the magnetic field.

Photoluminescence excitation (PLE) and temperature-dependent photoluminescence (PL) spectroscopies have been employed to interpret fine structure observed in the low-temperature PL spectra of GaAs/AlGaAs single quantum wells grown by molecular beam epitaxy under conditions of interrupted growth. Multiple peaks observed in the low-temperature PL spectra of similar samples grown by others have been held to be proof of monolayer steps in exceptionally smooth interfaces. We show that similar structure in the low-temperature PL spectra of our samples is not intrinsic. However, PLE or higher temperature PL spectroscopy yields unambiguous evidence for the model of interface smoothing due to growth interruption. [ABSTRACT FROM AUTHOR]

Cathodoluminescence scanning electron microscopy is utilized to investigate the stresses present underneath 0.4 μm gold layers deposited on GaAs/AlGaAs multiple quantum well structures grown by molecular beam epitaxy on GaAs substrates. Using the known stress dependence of excitonic lines in quantum wells, the magnitude of stress is determined to be about 1 kbar. The stress-induced change in the refractive index, attributed to photoelastic effect, is about 0.01 for the structures studied in the present work. [ABSTRACT FROM AUTHOR]

Photoluminescence and photoluminescence excitation spectroscopies are utilized to study excitons in GaAs/AlGaAs quantum wells (QW’s) fabricated by molecular beam epitaxy on a GaAs buffer layer grown on a Si substrate. The buffer layer was grown by metalorganic vapor phase epitaxy. The experimental results are understood in terms of a uniform biaxial tension of approximately 3 kbar present in the plane of growth for both the QW’s and the GaAs buffer. An important consequence of the biaxial tension is that for QW’s with well widths larger than ≊15 nm the light-hole and heavy-hole subbands cross each other in energy, resulting in a light-hole exciton energy lower than that of the heavy-hole exciton, opposite to the case of QW’s grown on GaAs substrates. [ABSTRACT FROM AUTHOR]

An InGaAs/GaAs strained-layer single quantum well waveguide-photodetector combination operating at a wavelength of 1.3 μm was fabricated on a GaAs substrate. An interdigitated metal-semiconductor-metal detector was deposited on top of the waveguide using Ti/Pt/Au for Schottky contacts. As expected, the responsivity of the detector increased with increasing single quantum well absorption in the waveguide and was sensitive to the polarization of the incident light. For TM polarization the responsivity of the detector was an order of magnitude lower at 1284 nm, compared to TE polarization, and exhibited weak dependence on wavelength, consistent with the transmission data. These results demonstrate for the first time a monolithically integrated 1.3 μm waveguide photodetector fabricated on a GaAs substrate. [ABSTRACT FROM AUTHOR]

GaAs/AlGaAs quantum wells (QWs), selectively intermixed by SiO2 capping and rapid thermal annealing, have been characterized on a microscale using spatially resolved photoluminescence (PL) spectroscopy. From the evolution of the PL spectra across the boundary between the unmixed and intermixed regions, it was concluded that the transition region is narrower than the 1.5 μm excitation beam diameter. The magnitude of the intermixing was also found to increase with the thickness of the oxide. The present intermixed QWs were found to be stable against subsequent thermal treatment below the temperature limit imposed by the intrinsic interdiffusion. These results demonstrate that the effective band gap of QWs, and their physical properties, can be adjusted by controlling the oxide thickness profile. [ABSTRACT FROM AUTHOR]