Probing of Unembedded Metallic Quantum Dots with Positrons

Conference · Fri Aug 01 00:00:00 EDT 2003

OSTI ID:15007890

Fischer, C G; Denison, A B; Weber, M H; Wilcoxon, J P; Woessner, S; Lynn, K G

We employed the two detector coincident Doppler Broadening Technique (coPAS) to investigate Ag, Au and Ag/Au alloy quantum dots of varying sizes which were deposited in thin layers on glass slides. The Ag quantum dots range from 2 to 3 nm in diameter, while the Ag/Au alloy quantum dots exhibit Ag cores of 2 nm and 3 nm and Au shells of varying thickness. We investigate the possibility of positron confinement in the Ag core due to positron affinity differences between Ag and Au. We describe the results and their significance to resolving the issue of whether positrons annihilate within the quantum dot itself or whether surface and positron escape effects play an important role.

• Research Organization: Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
• Sponsoring Organization: US Department of Energy (US)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 15007890
• Report Number(s): UCRL-JC-154745; TRN: US200423%%93
• Resource Relation: Conference: The 13th International Conference on Positron Annihilation, Kyoto (JP), 09/07/2003--09/13/2003; Other Information: PBD: 1 Aug 2003
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AFFINITY
ALLOYS
ANNIHILATION
CONFINEMENT
DOPPLER BROADENING
GLASS
POSITRONS
THICKNESS