Nakamura’s Diodes Display True Blue Emission

Researchers from Nichia Corp. in Anan, Japan, including the company's former head of research and development Shuji Nakamura, reported that they have produced 450-nm laser diodes. Nakamura's work has led to the commercial production of violet laser diodes with emissions of 390 to 420 nm.

The researchers produced the blue laser diodes with Nakamura's two-flow metallorganic chemical vapor deposition method, depositing an InGaN single quantum well structure on an epitaxially laterally overgrown GaN substrate. The 5-mW diodes have an estimated lifetime of approximately 200 h, which the group attributed to poor crystal quality in the InGaN well layer.

The team's results appear in the Jan. 3 issue of Applied Physics Letters.