| 1. |
- Laukkanen, P., et al.
(author)
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Formation and destabilization of Ga interstitials in GaAsN : Experiment and theory
- 2012
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In: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 86:19, s. 195205-
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Journal article (peer-reviewed)abstract
- Using first-principles total energy calculations we have found complex defects induced by N incorporation in GaAsN. The formation energy of the Ga interstitial atom is very significantly decreased due to local effects within the defect complex. The stability of the Ga interstitials is further increased at surfaces. The present results suggest that the energetically favorable Ga interstitial atoms are much more abundant in GaAsN than the previously considered N defects, which have relatively large formation energies. Our synchrotron radiation core-level photoemission measurements support the computational results. The formation of harmful Ga interstitials should be reduced by incorporating large group IV B atoms in GaAsN.
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| 2. |
- Dagnelund, Daniel, et al.
(author)
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Identification of an isolated arsenic antisite defect in GaAsBi
- 2014
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In: Applied Physics Letters. - : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 104:5, s. 052110-
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Journal article (peer-reviewed)abstract
- Optically detected magnetic resonance and photoluminescence spectroscopy are employed to study grown-in defects in GaAs0.985Bi0.015 epilayers grown by molecular beam epitaxy. The dominant paramagnetic defect is identified as an isolated arsenic antisite, As-Ga, with an electron g-factor of 2.03 +/- 0.01 and an isotropic hyperfine interaction constant A (900 +/- 620) x 10(-4) cm(-1). The defect is found to be preferably incorporated during the growth at the lowest growth temperature of 270 degrees C, but its formation can be suppressed upon increasing growth temperature to 315 degrees C. The As-Ga concentration is also reduced after post-growth rapid thermal annealing at 600 degrees C.
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| 3. |
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| 4. |
- Puustinen, J., et al.
(author)
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1.22 µm GaInNAs saturable absorber mirrors with tailored recovery time
- 2010
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In: Emerging trends and novel materials in photonics. - : American Institute of Physics (AIP). - 9780735408432 ; , s. 200-203
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Conference paper (peer-reviewed)abstract
- The effect of in-situ N-ion irradiation on the recombination dynamics of GaInNAs/GaAs semiconductor saturable absorber mirrors has been studied. The samples were fabricated by molecular beam epitaxy using a radio frequency plasma source for nitrogen incorporation in the absorber layers as well as for the irradiation. The recombination dynamics of irradiated samples were studied by pump-probe measurements. The recombination time of the absorbers could be reduced by increasing the irradiation time. The effect of the reduced recombination time on the pulse dynamics of a mode-locked laser setup was studied with a Bi-doped fibre laser. The pulse quality was found to improve with increased irradiation time and reduced recombination time, demonstrating the potential of the in-situ irradiation method for device applications.
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