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31 August 2009


Sumitomo boosts 520nm green InGaN laser to continuous-wave operation

Researchers at Sumitomo Electric Industries Ltd’s Semiconductor Technologies R&D Laboratories in Itami, Japan have demonstrated room-temperature continuous-wave operation of InGaN-based green laser diodes on semi-polar {2021} gallium nitride substrates emitting at a wavelength of 520nm (Yoshizumi et al, Appl. Phys. Express 2 (2009) 092101, 21 August).

The latest advance follows the team reporting in mid-July what it claimed was the first semiconductor laser diode emitting in the pure-green region of the spectrum, but under pulsed operation at room temperature. For the average pulsed laser emission wavelength of 520nm, the typical threshold current was 491mA (corresponding to a threshold current density of 8.2kA/cm2) and the threshold voltage was about 18V. For the longest lasing wavelength achieved (531nm), the threshold current was 924mA (Enya et al. Appl. Phys. Express 2 (2009) 082101, 17 July).

Previously, in late February Osram Opto Semiconductors GmbH of Regensburg, Germany demonstrated the first gallium nitride (GaN)-based laser with an emission wavelength of 500nm (blue-green), and at the end of May Japan's Nichia Corp reported blue-green lasing at 510-515nm (both using InGaN quantum wells grown on a c-plane GaN substrate).

In the latest development by Sumitomo Electric Industries, through improving the quality of epitaxial layers on {2021} GaN substrates using lattice-matched quaternary InAlGaN cladding layers and also through adopting a ridge-waveguide laser structure, continuous-wave operation at 520nm was achieved with a threshold current of 95mA (corresponding to a threshold current density of 7.9kA/cm2) and a threshold voltage of 9.4V.

See related items:

Sumitomo Electric claims first pure-green semiconductor laser

Nichia pushes InGaN lasers nearer to green via 515nm emission

Osram Opto claims first 500nm InGaN laser

Non-polar InGaN lasers near green light

Search: Sumitomo Electric Green laser diode GaN InGaN