A group of scientists researching zinc oxide (ZnO) films for flat panel displays, semiconductor light devices, and solar cells has created what they call a "highly efficient ultraviolet light emitting semiconductor" using a combination of zinc and magnesium oxide (ZnMgO) that, they claim, has the potential to raise the bar for high-density optical storage.
The scientists are members of the Thin Films Compound Semiconductors Team (COMSEM) team at the Research Center for Photovoltaics (RCPV) at Japan's National Institute of Advanced Industrial Science and Technology (AIST). "These results provide the way to high-density optical data processing, highly efficient and long-life white light sources, and high-performance large-area transparent conducting thin films for solar cells and flat-panel displays," according to one of the researchers.
The reference to high-density optical data processing means that the new semiconductors have the potential to read large amounts of data off of highly-compacted storage media like optical disks. The ZnO films are used in contrast to today's less-efficient semiconductors that use gallium nitride as a semiconductor, which "decreases the wavelength of the emitted light, and hence it is hard to realize light-emitting diodes that work in the ultraviolet wavelength region." However, the luminescence property of the Zinc Oxide semiconductors has proved to last longer under decreasing ultraviolet wavelengths that provide for higher storage capacities while maintaining an "efficient use of power," say the researchers.
The group does not mention what type of optical media the semiconductors will be used in, but they have made it clear that the technology has advantages over conventional technologies. It also doesn't appear that the group is onto something as promising as microholography, which Ars reported on earlier this week.
ZnMgO semiconductors may lead to more efficient and cheap storage options that use ultraviolet light-emitting technology as opposed to blue light-emitting technology used today. However, the scientists are really talking about increased storage factors of 1.2 to 1.5 times the density, rather than a whole order of magnitude. This increase in storage capacity will have additional implications, however, since polycarbonates—the material used to make optical media—are unstable when irradiated by UV light. Judging by the huge investments in polycarbonate-based technologies, it is more likely that a generation of blue light-emitting zinc oxide lasers will replace the current generation, rather than a wavelength shift into the ultraviolet.
For more information, check out the AIST web site.
http://www.aist.go.jp/aist_e/latest_research/2007/20070710/20070710.html