17 Jun 2002
New highly-crystalline passivated silicon nanocrystals exhibit bright fluorescent radiation in the visible range.
Courtesy of Fibers.Org
US-based Field Emission Picture Element Technology, subsidiary of SI Diamond Technology (SIDT) has built a system to produce silicon nanoclusters. These nanocrystals show efficient blue and green photoluminescence with very high quantum yields at room temperature.
Nanocrystals, or quantum dots, in the range of 2-50 nm have different optical properties than the bulk material. As they grow in size, their properties approach bulk values and the band gap that defines the materials' optical and electronic properties changes.
The nanocrystals exhibit a significant blue shift in optical properties from the bulk infrared band-gap energy to the visible range and, as the band-gap varies with crystal size, the fluorescent wavelength can be tuned by controlling that size.
Although still in the development stage, SIDT sees the materials being used for displays, optical memory, micro-opto-electronic devices and fluorescent tags in biological systems.
The company is planning to form a center to develop nanocrystal applications to bring the technology to market, and is inviting groups interested in the new materials to join the center.