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.
Fabrication of wirelike InAs quantum dots on 2°-off GaAs (100) substrates by changing the thickness of the InAs layer
Wirelike InAs quatum dots (QDs) grown on 2°-off (100) GaAs substrates by changing the thickness of the InAs layer were successfully fabricated. The sizes of the InAs QDs along the step lines increased with increasing the thickness of the InAs layer, and their increases were attributed to transform of the InAs QDs into the wirelike InAs QDs. The optimal thicknesses of the InAs layers for the wirelike QDs and the interval of the wirelike QDs were significantly affected by the terrace width resulting from the bunching effect due to the thickness variations of the GaAs buffer layers grown on 2°-off (100) GaAs substrates. These results indicate that these wirelike InAs QDs are useful for applications in nanoelectronic devices, such as wrap gate single electron transistors.
5.63 and 5.80 MeV levels of Ne20; de-excitation branching
Abstract The ratio Г γ /Г for the 5.63 and 5.80 MeV levels of Ne 20 has been determined to be 0.077 (±0.008) and −4 , respectively, by using the C 12 (C 12 , α)Ne 20 reaction and determining the fraction of the events in which the alpha-particle and the Ne 20 recoil are present in coincidence at the kinematically correct angles. In both cases these results in themselves are shown to imply radiative E1 transition (5.63→1.63 and 5.80→0, respectively) probabilities ⪡5 × 10 −5 Weisskopf units. When taken together with the life-time for the 5.63 MeV level measured by Evans et al . values of Г( E1 ) ≲ 5 × 10 −6 and Г α ≈ 6% of the particle estimate are obtained for this state.