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| 2. |
- Tångring, Ivar, 1978, et al.
(författare)
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1.58 µm InGaAs quantum well laser on GaAs
- 2007
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Ingår i: Applied Physics Letters. ; 91, s. 221101-
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate the 1.58 µm emission at room temperature from a metamorphic In0.6Ga0.4As quantum well laser grown on GaAs by molecular beam epitaxy. The large lattice mismatch was accommodated through growth of a linearly graded buffer layer to create a high quality virtual In0.32Ga0.68As substrate. Careful growth optimization ensured good optical and structural qualities. For a 1250×50 µm2 broad area laser, a minimum threshold current density of 490 A/cm2 was achieved under pulsed operation. This result indicates that metamorphic InGaAs quantum wells can be an alternative approach for 1.55 µm GaAs-based lasers.
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| 3. |
- Tångring, Ivar, 1978, et al.
(författare)
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A study of the doping influence on strain relaxation of graded composition InGaAs layers grown by molecular beam epitaxy
- 2009
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Ingår i: Journal of Crystal Growth. - 0022-0248. ; 311, s. 1684-
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the role of p- and n-type doping in strain relaxation of graded composition InGaAs layers grown by molecular beam epitaxy. It is found that p-type Be-doping can improve material properties, resulting in smaller surface roughness and lower threading dislocation density, while n-type Si-doping has an opposite effect. The effect is strongly dependent on the grading profile, with linear grading showing small differences, while there is a significant difference when an exponential grading is used. Since doping is essential for many types of devices, these results are useful for improving the material properties and performance of metamorphic devices.
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| 5. |
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| 6. |
- Tångring, Ivar, 1978, et al.
(författare)
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Manipulation of strain relaxation in metamorphic heterostructures
- 2007
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Ingår i: Applied Physics Letters. ; 90, s. 071904-
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Tidskriftsartikel (refereegranskat)abstract
- The authors have discovered that high doping densities in an alloy graded InGaAs buffer havedramatic effects on strain relaxation dynamics and consequently surface and optical qualities inmetamorphic heterostructures. Compared with undoped graded buffers, the use of Be dopingsignificantly improves structural, surface, and optical qualities while the use of Si dopingdeteriorates all these properties. This discovery is significant for the realization of metamorphicoptoelectronic devices.
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| 7. |
- Tångring, Ivar, 1978, et al.
(författare)
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Metamorphic growth of 1.25 – 1.29 µm InGaAs quantum well lasers by molecular beam epitaxy
- 2007
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Ingår i: Journal of Crystal Growth. - : Elsevier BV. - 0022-0248. ; 301:SPEC. ISS., s. 971-974
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate 1.25–1.29 μm metamorphic laser diodes grown on GaAs by molecular beam epitaxy (MBE) using an alloy-graded buffer layer (GBL). Use of Be in the GBL is effective to reduce surface/interface roughness and improves optical quality. The RMS surface roughness of the optimized metamorphic laser is only two atomic monolayers for 1×1 μm2. Cross-sectional transmission electron microscopy (TEM) images confirm that most dislocations are blocked in the GBL. Ridge waveguide lasers with 4 μm wide ridge were fabricated and characterized. The average threshold current under the pulsed excitation is in 170–200 mA for a cavity length of 0.9–1.5 mm. This value can be further reduced to about 100 mA by high-reflectivity coating. Lasers can work in an ambient temperature up to at least 50 °C.
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| 8. |
- Wang, Shu Min, 1963, et al.
(författare)
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Metamorphic InGaAs Materials and Telecom Lasers
- 2009
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Ingår i: International Conference on Materials and Advanced Technology (ICMAT) 2009, Singapore, June 28 - July 3, 2009. (invited paper).
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Konferensbidrag (refereegranskat)
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| 9. |
- Zhao Ternehäll, Huan, 1982, et al.
(författare)
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Comparison of optical and structural quality of GaIn(N) As analog and digital quantum wells grown by molecular beam epitaxy
- 2008
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Ingår i: Semiconductor Science and Technology. - : IOP Publishing. - 0268-1242 .- 1361-6641. ; 23:12, s. 125002-
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Tidskriftsartikel (refereegranskat)abstract
- A set of Ga0.625In0.375(N) As single quantum well (QW) samples with the identical total amounts of Ga and In and QW thicknesses was designed and grown by both the analog and the digital methods using molecular beam epitaxy. The N exposure time in the GaInNAs samples was kept the same. The inter-band gap recombination in the analog and the digital InGaAs QWs appears in a similar transition energy range as a result of In segregation. Temperature-dependent photoluminescence (PL) measurements were performed on the GaInNAs samples. An S-shaped dependence of the transition energy on temperature was observed in the digital GaInNAs QWs but not in the analog GaInNAs QW. Post-growth rapid thermal annealing had remarkably different effects on the PL intensity: an increase for the analog InGaAs QW and for the analog and digital GaInNAs QWs, but a decrease for the digital InGaAs QW with increasing annealing temperature. The GaIn(N) As samples grown by the digital method showed weaker PL intensities and smaller wavelength blue-shifts than the similar samples grown by the analog method. Possible strain relaxation mechanisms are discussed.
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