Research to realize long-wavelength, GaInNAs quantum well lasers has been intense in the past three years. The results have been very promising considering the relative immaturity and challenges of this new materials system. This paper reviews both the materials challenges and progress in growth of the metastable GaInNAs alloys required to reach the 1.3–1.55 μm communication wavelengths and the challenges and progress in device design for both vertical-cavity surface-emitting lasers and higher power edge-emitting lasers.

https://iopscience.iop.org/article/10.1088/0268-1242/17/8/317/pdf

GaInNAs long-wavelength lasers: progress and challenges

A brief review on the present knowledge of the electronic properties of the Ga(In)NAs ternary and quaternary alloys is given mainly from an experimental perspective. The discussion is focused on Ga(In)NAs with low N composition (< 10 %), where a large amount of experimental work has been done. Important fundamental electronic properties of the material system are analyzed with the emphasis on the nature of the giant band gap bowing in the alloy and nitrogen-induced modifications of the electronic structure of the conduction band. The current knowledge of the key material parameters, relevant for the device applications, such as electron effective mass, recombination processes and band alignment in Ga(In)NAs/GaAs heterostructures, is also reviewed.

/pdf/electronic-properties-of-ga-in-nas-alloys-4u4hxqn7tn.pdf

Electronic Properties of Ga(In)NAs Alloys

Positron-annihilation measurements and nuclear reaction analysis [utilizing the 14N(d,p)15N and 14N(d,He)12C reactions] in conjunction with Rutherford backscattering spectrometry in the channeling geometry were used to study the defects in as-grown Ga(In)NAs materials grown by molecular beam epitaxy using a radio-frequency plasma nitrogen source. Our data unambiguously show the existence of vacancy-type defects, which we attribute to Ga vacancies, and nitrogen interstitials in the as-grown nitride–arsenide epilayers. These point defects, we believe, are responsible for the low luminescence efficiency of as-grown Ga(In)NAs materials and the enhanced diffusion process during annealing.

Origin of improved luminescence efficiency after annealing of Ga(In)NAs materials grown by molecular-beam epitaxy

Highly mismatched semiconductor alloys such as GaNxAs1 − x and GaBixAs1 − x have several novel electronic properties, including a rapid reduction in energy gap with increasing x and also, for GaBiAs, a strong increase in spin-orbit-splitting energy with increasing Bi composition. We review here the electronic structure of such alloys and their consequences for ideal lasers. We then describe the substantial progress made in the demonstration of actual GaInNAs telecommunication (telecom) lasers. These have characteristics comparable to conventional InP-based devices. This includes a strong Auger contribution to the threshold current. We show, however, that the large spin-orbit-splitting energy in GaBiAs and GaBiNAs could lead to the suppression of the dominant Auger recombination loss mechanism, finally opening the route to efficient temperature-stable telecomm and longer wavelength lasers with significantly reduced power consumption.

Band engineering in dilute nitride and bismide semiconductor lasers

Highly mismatched semiconductor alloys such as GaNAs and GaBiAs have several novel electronic properties, including a rapid reduction in energy gap with increasing x and also, for GaBiAs, a strong increase in spin orbit- splitting energy with increasing Bi composition. We review here the electronic structure of such alloys and their consequences for ideal lasers. We then describe the substantial progress made in the demonstration of actual GaInNAs telecomm lasers. These have characteristics comparable to conventional InP-based devices. This includes a strong Auger contribution to the threshold current. We show, however, that the large spin-orbit-splitting energy in GaBiAs and GaBiNAs could lead to the suppression of the dominant Auger recombination loss mechanism, finally opening the route to efficient temperature-stable telecomm and longer wavelength lasers with significantly reduced power consumption.

/pdf/band-engineering-in-dilute-nitride-and-bismide-semiconductor-4zgdqfbmvz.pdf

GaInAsN/GaAs double quantum well (DQW) lasers have been grown by solid source molecular beam epitaxy (MBE). Room-temperature pulsed operation is demonstrated for a ridge waveguide laser diode at a wavelength of 1517 nm. This is the first report of room-temperature laser emission in the 1.5 /spl mu/m range based on GaAs.

GaInAsN/GaAs laser diodes operating at 1.52 [micro sign]m

High frequency characterisation of double quantum well GaInAsN laser diodes emitting at 1.28 /spl mu/m is reported. The 3 dB bandwidth of ridge waveguide lasers was measured to be 7.8 GHz at 120 mA under CW operation demonstrating the potential for high speed operation of these devices.

M. Reinhardt

Papers

GaInAsN/GaAs laser diodes operating at 1.52 [micro sign]m

7.8 GHz small-signal modulation bandwidth of 1.3 [micro sign]m DQW GaInAsN/GaAs laser diodes