Optical properties of In/sub 0.8/Ga/sub 0.2/As self-assembled quantum dots on SiO/sub 2/-patterned [001] vicinal GaAs substrates
In this study, we investigated the optical properties of InGaAs SAQD on SiO/sub 2/-patterned exact and 5 /spl deg/-off [001] GaAs substrates. Also, we compared the discrete nature of the density of states in SAQDs for both starting materials.
Optical properties of InAs quantum dots formed on GaAs pyramids
Optical properties of InAs quantum dots on GaAs pyramidal structures formed by selective area metal organic vapor phase epitaxy have been studied with low-temperature excitation powerdependent microphotoluminescence (μ-PL) and microphotoluminescence excitation (μ-PLE) spectroscopy. The power-dependent μ-PL spectra show well-defined ground and excited states whose interlevel energy spacings are estimated to be about 21 meV. These experimental results demonstrate the discrete nature of zero-dimensional density of states in position and number controlled InAs quantum dots (QDs) selectively grown on GaAs pyramids. We have also observed relative strong PLE peaks which are ascribed to the multiple longitudinal optical phonon resonance. Excited states and carrier relaxation of InAs QDs formed on GaAs pyramids are discussed.
Conductance oscillation characteristics of GaAs Schottky wrap-gate single-electron transistors
Abstract Conductance oscillation characteristics in GaAs-based Schottky wrap gate (WPG) single-electron transistors (SETs) were investigated both experimentally and theoretically in view of application as a key switching device in future quantum-integrated circuits. Fabricated WPG SETs showed that clear conductance oscillation characteristics with a small number of high conductance peaks. A simple theory based on a quantum mechanical treatment reproduced qualitatively the features of the experimentally observed conductance peaks, indicating that the resonant tunneling contributes to currents in the WPG SETs. However, quantitatively, a discrepancy existed between theory and experiment on the temperature dependence of peak heights.