Bismuth-containing semiconductor forms mid-IR laser diode

July 10, 2017
An electrically injected laser diode that relies on a bismuth-containing semiconductor and that emits continuous-wave in the mid-infrared at a 2.52 μm wavelength and a temperature of 80 K has been reported.
Content Dam Lfw Print Articles 2017 07 1707lfw Nb F2
Content Dam Lfw Print Articles 2017 07 1707lfw Nb F2
Content Dam Lfw Print Articles 2017 07 1707lfw Nb F2
Content Dam Lfw Print Articles 2017 07 1707lfw Nb F2
Content Dam Lfw Print Articles 2017 07 1707lfw Nb F2

An electrically injected laser diode that relies on a bismuth-containing semiconductor and that emits continuous-wave (CW) in the mid-infrared (mid-IR) at a 2.52 μm wavelength and a temperature of 80 K has been reported by a group of researchers at the Université de Montpellier and CNRS (both in Montpellier, France) and the Paul-Drude-Institut für Festkörperelektronik (Berlin, Germany). The laser can also emit pulsed light at a 2.71 μm wavelength at room temperature.

Grown using molecular-beam epitaxy (MBE), the device is based on gallium arsenide bismuth (GaAs1-xBix) in the form of GaSbBi layers and GaSbBi/GaSb multiple quantum-well (MQW) structures with compositional proportions of GaSb0.885Bi0.115/GaSb. The researchers took great care to optimize the growth conditions to prevent the formation of droplets at the surface of the III-V-Bi epilayers, which would reduce performance. Atomic-force-microscope (AFM) measurements showed a root-mean-squared (RMS) roughness under 0.2 nm. Experimentally, at room temperature, the threshold current density for the 10 × 1160 μm2 area diode was 4.22 kA/cm2 under pulsed operation, while at 80 K, the threshold-current density was 586 A/cm2. The researchers aim to improve the GaSbBi/GaSb MQW structural quality, which will reduce the rather high threshold-current density. Reference: O. Delome et al., Appl. Phys. Lett. (2017); http://dx.doi.org/10.1063/1.4984799.

About the Author

John Wallace | Senior Technical Editor (1998-2022)

John Wallace was with Laser Focus World for nearly 25 years, retiring in late June 2022. He obtained a bachelor's degree in mechanical engineering and physics at Rutgers University and a master's in optical engineering at the University of Rochester. Before becoming an editor, John worked as an engineer at RCA, Exxon, Eastman Kodak, and GCA Corporation.

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