Tuning the emission wavelength of Si nanocrystals in SiO{sub 2} by oxidation
- FOM Institute for Atomic and Molecular Physics, Kruislaan407, 1098SJAmsterdam (The Netherlands)
- Thomas J. Watson Laboratory of Applied Physics, California Institute of Technology, Pasadena, California91125 (United States)
Si nanocrystals (diameter 2{endash}5 nm) were formed by 35 keV Si{sup +} implantation at a fluence of 6{times}10{sup 16}Si/cm{sup 2} into a 100 nm thick thermally grown SiO{sub 2} film on Si (100), followed by thermal annealing at 1100{degree}C for 10 min. The nanocrystals show a broad photoluminescence spectrum, peaking at 880 nm, attributed to the recombination of quantum confined excitons. Rutherford backscattering spectrometry and transmission electron microscopy show that annealing these samples in flowing O{sub 2} at 1000{degree}C for times up to 30 min results in oxidation of the Si nanocrystals, first close to the SiO{sub 2} film surface and later at greater depths. Upon oxidation for 30 min the photoluminescence peak wavelength blueshifts by more than 200 nm. This blueshift is attributed to a quantum size effect in which a reduction of the average nanocrystal size leads to emission at shorter wavelengths. The room temperature luminescence lifetime measured at 700 nm increases from 12 {mu}s for the unoxidized film to 43 {mu}s for the film that was oxidized for 29 min. {copyright} {ital 1998 American Institute of Physics.}
- OSTI ID:
- 627888
- Journal Information:
- Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 20 Vol. 72; ISSN APPLAB; ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
Similar Records
Defect-related versus excitonic visible light emission from ion beam synthesized Si nanocrystals in SiO{sub 2}
Formation and optical properties of GaSb quantum dots epitaxially grown on Si substrates using an ultrathin SiO{sub 2} film technique