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 single- or double-row aligned self-assembled quantum dots by utilizing SiO2-patterned vicinal (001) GaAs substrates
We investigated the formation of In0.8Ga0.2As self-assembled quantum dots (SAQDs) grown on SiO2-patterned 1°, 2°, and 5°-off (001) GaAs substrates by selective area metalorganic vapor phase epitaxy technique. The SiO2 patterns were filled with various stripe opening windows along the misorientation direction of the substrates. During the growth of the GaAs buffer layer on the opening regions, the steps on the (001) top facet was affected by the widths of the (001) top facet and the misorientation angles of the substrates. Single- or double-row aligned In0.8Ga0.2As SAQDs having definite interval were successfully fabricated on the (001) top facet with optimized top width and periodicity of step bunching. These results indicate that the selective growth technique of SAQDs by utilizing SiO2-patterned vicinal substrates is promising for nanoelectronic device applications such as single-electron memory devices.
Training and maintaining the performance of dogs (Canis familiaris) on an increasing number of odor discriminations in a controlled setting
Abstract The number of substances detector dogs are trained to detect varies depending on the mission of the agency they serve. No studies have been conducted concerning how training multiple odor discriminations affects detection performance and refresher training requirements. This study used a controlled field setting to examine the effects of training dogs to detect multiple substances on their subsequent detection performance and refresher training requirements. Dogs were first trained to detect a single odor. Their detection performance was tested 10 days later and refresher training was then given to bring their performance back up to a predetermined standard. Following refresher training, detection of a new substance was trained, and approximately 10 days later the detection of both trained substances was tested. This sequence of testing, refresher training, and new odor training continued every 10 days until the dogs had been trained and tested on 10 odors. The detection of previously learned odors did not decrease as the number of substances trained increased. In fact, the amount of training required to refresh detection performance and to train new odor discriminations tended to decrease as more odor discriminations were trained.