Methods of controlling the emission wavelength in InAs/GaAsN/InGaAsN heterostructures on GaAs substrates
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Methods of Controlling the Emission Wavelength in InAs/GaAsN/InGaAsN Heterostructures on GaAs Substrates V. V. Mamutina^, A. Yu. Egorova, b, N. V. Kryzhanovskayab, V. S. Mikhrina, A. M. Nadtochya, and E. V. Pirogova, b aIoffe
Physicotechnical Institute, Russian Academy of Sciences, St. Petersburg, 194021 Russia ^e-mail: [email protected] bSt. Petersburg Physics and Technology Center for Research and Education, Russian Academy of Sciences, St. Petersburg, 194021 Russia Submitted November 6, 2007; accepted for publication November 19, 2007
Abstract—Studies of the properties of InGaAsN compounds and methods of controlling the emission wavelength in InAs/GaAsN/InGaAsN heterostructures grown by molecular beam epitaxy on GaAs substrates are reviewed. The results for different types of heterostructures with quantum-size InGaAsN layers are presented. Among those are (1) traditional InGaAsN quantum wells in a GaAs matrix, (2) InAs quantum dots embedded in an (In)GaAsN layer, and (3) strain-compensated superlattices InAs/GaAsN/InGaAsN with quantum wells and quantum dots. The methods used in the study allow controllable variations in the emission wavelength over the telecommunication range from 1.3 to 1.76 µm at room temperature. PACS numbers: 42.55.Px, 73.21.Cd, 73.21.Fg, 73.21.La, 73.40.Kp, 78.55.-m, 78.67.Pt DOI: 10.1134/S1063782608070105
1. INTRODUCTION At the present time, many researchers are concentrating their efforts on the development of efficient light emitters that operate in the wavelength range 1.3– 1.55 µm corresponding to the spectral windows of optical fiber and, at the same time, present alternatives to InP-based lasers available in the market. One way to obtain emission in the range 1.3–1.55 µm based on GaAs substrates is through the use of InGaAsN compounds. When nitrogen is added to GaAs, the band gap of the alloy exhibits a uniquely profound decrease nontrivial for III–V compounds (180 meV for the nitrogen content of only 1% [1]). Introduction of indium into the GaAsN alloy tends to compensate the nitrogen-induced compression of the lattice and to decrease the band gap even more. Thus, with the InGaAsN compounds, it is possible to produce layers that are close in lattice constant to GaAs and emit in the near-infrared range from 1.3 to 1.55 µm. The main advantages of the InGaAsN compounds used in lasers and grown on GaAs substrates over the InGaAs/InGaAsP and InGaAsP/InP heterostructures (HSs) widely used at the present time can be listed as follows: better temperature stability of laser characteristics because of larger band offsets and, as a consequence, larger localization energies of carriers in the active region; the feasibility of the development of surface-emitting lasers with bulk AlGaAs/GaAs Bragg mirrors; and higher thermal conductivity of the layers in the structures. However, increasing emission wavelength to 1.55 µm requires an increase of the indium and nitro-
gen content, and therefore, because of InGaAsN active region structural properties deterioration, one observes a
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