Japanese researchers have developed a new ultraviolet semiconducting material that could provide various new functions, such as a higher optical recording density and the excitation of white-light-emitting fluorescent materials. The researchers behind the development are members of the National Institute of Advanced Industrial Science and Technology (AIST) in Japan.

The high emission efficiency of this newly developed zinc oxide (ZnO) semiconducting material has been accomplished by preparing a high-quality single crystalline thin film by the molecular beam epitaxy method. The light emission efficiency of the conventional ultraviolet-emitting semiconducting materials, such as gallium nitride, usually decreases with decreasing the wavelength of the emitted light. However, the newly developed material shows a remarkable increase in emission efficiency when the wavelength is decreased with increasing magnesium concentration, according to the researchers.

The basic structure of light emission devices is generally three-layered structure, where the light emitting active layer is sandwiched in between two barrier layers that block the transmission of light and electrons. The structure of the ZnO-based light emission devices which has been examined so far consists of ZnO as the active layer and "ZnMgO" as the two barrier layers. However, the researchers have discovered that "ZnMgO" has a far higher light emission efficiency than ZnO, so the ZnMgO is expected to be the material that they will use as an active layer in future semiconductor devices.



The material can be used for highly efficient ultraviolet light-emitting diodes, semiconductor lasers, and high-performance sources of white light.

For additional information visit www.aist.go.jp.