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- Dagnelund, Daniel, 1980-, et al.
(author)
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Optically detected cyclotron resonance studies of InGaNAs/GaAs structures
- 2007
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In: Physics of semiconductors : 28th International Conference on the Physics of Semiconductors, ICPS 2006, Vienna, Austria, 24-28 July 2006. - : American Institute of Physics (AIP). - 9780735403970 ; , s. 383-384
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Conference paper (other academic/artistic)abstract
- We report on our recent results from a systematic study of layered structures containing an InGaNAs/GaAs quantum well (QW), by the optically detected cyclotron resonance (ODCR) technique. By monitoring photoluminescence (PL) emissions from various layers the predominant ODCR peak is shown to be related to carriers with a 2D character and an effective mass of 0.51 m∗e. The responsible carriers are ascribed to be electrons in GaAs/AlAs superlattices (SL) that are employed in the laser structures to prevent carrier leak by sandwiching the InGaNAs/GaAs QW. This conclusion is based on the following observations: (a) the ODCR peak is only observed in the structures containing the SL; (b) the effective mass value determined by the ODCR peak is independent of In and N compositions; (c) the same ODCR peak is also observed by monitoring PL from the SL. Unfortunately no ODCR signal related to InGaNAs was observed
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- Dagnelund, Daniel, 1980-, et al.
(author)
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Optically detected cyclotron resonance studies of InxGa1-xNyAs1-y/GaAs quantum wells sandwiched between type-II AlAs/GaAs superlattices.
- 2007
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In: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 101, s. 073705-
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Journal article (peer-reviewed)abstract
- We report on our results from a systematic study of layered structures containing an InGaNAs/GaAs single quantum well (SQW) enclosed between staggered type II AlAs/GaAs superlattices (SL), by the photoluminescence (PL) and optically detected cyclotron resonance (ODCR) techniques. Besides the ODCR signal known to originate from electrons in GaAs, the predominant ODCR peak is shown to be related to carriers with a two-dimensional character and a cyclotron resonance effective mass of m*[approximate](0.51-0.56)m0. The responsible carriers are ascribed to electrons on the ellipsoidal equienergy surface at the AlAs X point of the Brillouin zone within the SL, based on results from angular and spectral dependences of the ODCR signal. No ODCR signal related to the InGaNAs SQW was detected, presumably due to low carrier mobility despite the high optical quality. Multiple absorption of photons with energy below the band gap energy of the SL and the GaAs barriers was observed, which bears implication on the efficiency of light-emitting devices based on these structures.
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- Dagnelund, Daniel, 1980-, et al.
(author)
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Spin resonance spectroscopy of grown-in defects in Ga(In)NP alloys
- 2008
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In: 7th International Conference on Physics of Light-Matter Coupling in Nanostructures, 2007. - : Elsevier Ltd.. ; , s. 620-625
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Conference paper (peer-reviewed)abstract
- We employ the optically detected magnetic resonance (ODMR) technique to study and identify important grown-in defects in Ga(In)NP grown by molecular-beam epitaxy (MBE). Several types of defects were revealed from ODMR studies. The dominant defects were found to be related to Ga interstitials, evident form their characteristic hyperfine interaction arising from the spin interaction between the electron and the Ga nucleus. Some other as yet unidentified intrinsic defects were also found to be commonly present in the alloys. The effects of growth conditions (ion bombardment, N2 gas flow, etc.) and post-growth rapid thermal annealing on the formation of these defects were studied in detail, shedding light on the formation mechanism of defects.
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- Izadifard, Morteza, 1965-, et al.
(author)
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Evaluation of optical quality and defect properties of GaNxP1−x alloys lattice matched to Si
- 2004
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 85, s. 6347-
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Journal article (peer-reviewed)abstract
- By using a variety of optical characterization techniques, including cathodoluminescence, temperature-dependent cw- and time-resolved photoluminescence (PL), and PL excitation spectroscopies, high optical quality of the GaN0.018P0.982 epilayers lattice matched to Si substrates is demonstrated and is shown to be comparable to that of the “state-of-the-art” GaNP alloys grown on GaP substrates. The growth of GaNP on Si is, however, found to facilitate the formation of several point defects, including complexes involving Ga interstitial atoms (Gai).
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- Thinh, N. Q., et al.
(author)
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Formation of Ga interstitials in (Al,In)yGa1-yNxP1-x alloys and their role in carrier recombination
- 2004
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 85, s. 2827-
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Journal article (peer-reviewed)abstract
- Formation of complex defects involving a Ga interstitial (Gai) in (Al,In)yGa1-yNxP1-x alloys and their effects on optical quality are studied by photoluminescence (PL) and optically detected magnetic resonance spectroscopies. Introduction of these defects is shown to be largely promoted by incorporation of N. In quaternary alloys, concentrations of the defects are found to critically depend on the group III atoms that replace Ga, i.e., it is largely enhanced by the presence of Al in alloys, but is only marginally affected by In incorporation. The effect is attributed to differences in surface adatom mobilities of the group III atoms involved and their bonding strength with N. The revealed Gai complexes are shown to act as efficient nonradiative recombination centers degrading the PL efficiency. The defects exhibit high thermal stability and can only be partially removed by postgrowth rapid thermal annealing.
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- Thinh, N.Q., et al.
(author)
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Ga-interstitial related defects in Ga(Al)NP
- 2005
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In: 27th Int. Conf. on the Physics of Semicond,2004. - : American Institute of Physics (AIP). ; , s. 259-260
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Conference paper (other academic/artistic)abstract
- Twogrown-in Ga interstitial (Gai) defects in Ga(Al)NP are identified byoptically detected magnetic resonance (ODMR), from the characteristic hyperfine (HF)structure associated with the nuclear spin I=3/2 of the Gai.Both defects are concluded to be Gai-related complexes. Effects ofAl and N compositions on the HF structure shed lighton local surrounding of the Gai. ©2005 American Institute ofPhysics
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