GaN lasers have been reported to fail due to degradation of ohmic contacts at during laser operation. To avoid these problems, one must either lower the operating current of the laser, extract the heat better, or make more robust contacts. The CREE work indicates that the use of a substrate with high thermal conductivity is may be effective at lowering the operating temperature, but an efficient laser structure is also necesary. Ultimately, all three strategies may be necessary. The breakthrough was accomplished by scientists at Cree who designed and fabricated the device using Cree's silicon carbide wafers combined with a proprietary gallium nitride thin film process.
Preliminary measurements indicate a device lifetime of greater than a few minutes.
This is a milestone toward achieving a commercially viable laser, but we still have a lot of development work ahead of us. The next step is to improve device performance and process repeatability. The shorter wavelength of blue light as compared to longer wavelength red or infrared lasers used today is responsible for the increased storage capability. That funding has been critical in achieving the blue laser result said Cree's president, Neal Hunter. This demonstration is a critical step to realizing a key military component.