Transistor laser operates at room temperature
The University of Illinois at Urbana-Champaign (UIUC) research team that created the first transistor laser have now built a room temperature successor.
Operating at 25°C, their latest transistor laser delivers 3 GHz continuous wave output with emission at 1006 nm.
That represents an improvement over last year's results (see related story), as the first devices required cooling to 200K, and could only be driven in pulsed mode.
The latest transistor laser was grown on a semi-insulating GaAs substrate, and contained an InGaAs quantum well in the base region, and an 0.025 µm-thick InGaP emitter layer.
Device fabrication required eight mask layers for three wet-chemical etching steps, three dry etching steps, and three metallization steps, to form a transistor laser with a 850 µm Fabry-Perot cavity and a 2.2 µm-wide emitter.
"The transistor laser is still a primitive, laboratory device that will require a lot more work," remarked Nick Holonyak, a member of the research team.
"We expect it will operate at much higher speeds when it is fully developed, and play an important role in electronic-photonic circuits."
More details concerning the device's fabrication and operating characteristics can be found in the September 26 issue of Applied Physics Letters.
