Influence of Ge content on the optical properties of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>X</mml:mi></mml:math>and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>W</mml:mi></mml:math>centers in dilute Si-Ge alloys

Leitão, J. P.; Carvalho, Alexandra; Coutinho, J.; Pereira, Rui N.; Santos, Nuno N.M.; Ankiewicz, A. O.; Соболев, Н. А.; Barroso, M.; Hansen, J. Lundsgaard; Larsen, A. Nylandsted; Briddon, P.R.

doi:10.1103/physrevb.84.165211

Cited by 17 publications

(17 citation statements)

References 65 publications

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“…Among the five I 3 structures studied by Carvalho et al (2005), only the I 3 -I structure has a level in the band gap, a donor level at E V +0.15 eV. This was confirmed recently by Leitão et al (2011) who found the level to be at E V +0.18 eV. Thus, only the I 3 -I structure will be electrically active, will show photoluminescence activity, and is the only tri-interstitial that could be detected by EPR as this method can only detect defects with an unpaired spin.…”

Section: The Tri-interstitialsupporting

confidence: 50%

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Electron and Proton Irradiation of Silicon

Larsen

Mesli

2015

Semiconductors and Semimetals

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Section: The Tri-interstitialsupporting

confidence: 50%

“…The W-center shows a zero-phonon emission line at 1018 meV; it starts to appear in the PL spectra at around room temperature and is maximized after annealing at $300°C and disappears at $400°C (Leitão et al, 2011). The symmetry of the W-center is trigonal, showing a unique phonon sideband at 565 cm À1 .…”

Section: The Tri-interstitialmentioning

confidence: 94%

Electron and Proton Irradiation of Silicon

Larsen

Mesli

2015

Semiconductors and Semimetals

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“…The non-radiative de-excitation channels were investigated considering an equation that takes into account the thermal redistribution of charge carriers between the radiative state and non-radiative discrete states (or a band) of higher energy [64]:…”

Section: Resultsmentioning

confidence: 99%

Substrate and Mg doping effects in GaAs nanowires

Kannappan¹,

Sédrine²,

Teixeira³

et al. 2017

Beilstein J. Nanotechnol.

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Mg doping of GaAs nanowires has been established as a viable alternative to Be doping in order to achieve p-type electrical conductivity. Although reports on the optical properties are available, few reports exist about the physical properties of intermediate-to-high Mg doping in GaAs nanowires grown by molecular beam epitaxy (MBE) on GaAs(111)B and Si(111) substrates. In this work, we address this topic and present further understanding on the fundamental aspects. As the Mg doping was increased, structural and optical investigations revealed: i) a lower influence of the polytypic nature of the GaAs nanowires on their electronic structure; ii) a considerable reduction of the density of vertical nanowires, which is almost null for growth on Si(111); iii) the occurrence of a higher WZ phase fraction, in particular for growth on Si(111); iv) an increase of the activation energy to release the less bound carrier in the radiative state from nanowires grown on GaAs(111)B; and v) a higher influence of defects on the activation of nonradiative de-excitation channels in the case of nanowires only grown on Si(111). Back-gate field effect transistors were fabricated with individual nanowires and the p-type electrical conductivity was measured with free hole concentration ranging from 2.7 × 1016 cm−3 to 1.4 × 1017 cm−3. The estimated electrical mobility was in the range ≈0.3–39 cm2 /Vs and the dominant scattering mechanism is ascribed to the WZ/ZB interfaces. Electrical and optical measurements showed a lower influence of the polytypic structure of the nanowires on their electronic structure. The involvement of Mg in one of the radiative transitions observed for growth on the Si(111) substrate is suggested.

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“…With respect to the X line, Carvalho et al suggested the tetra-interstitial Si cluster configuration proposed by Arai et al as X PL center, despite that its donor level did not agree with experimental values, and there were some discrepancies of the calculated LVMs with experiments [17]. Thus, the atomistic configurations of the W and X PL centers in c-Si remain unclear [18].…”

Section: Introductionmentioning

confidence: 85%

Insights on the atomistic origin of X and W photoluminescence lines inc-Si fromab initiosimulations

Santos¹,

Aboy²,

López³

et al. 2016

J. Phys. D: Appl. Phys.

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Abstract.We have used atomistic simulations to identify and characterize interstitial defect cluster configurations candidates to W and X photoluminescence centers in crystalline Si. The configurational landscape of small self-interstitial defect clusters has been explored through nanosecond annealing and implantation recoil simulations using classical molecular dynamics. Among the large collection of defect configurations obtained, we have selected those defects with the trigonal symmetry of the W center, and the tetrahedral and tetragonal symmetry of the X center. These defect configurations have been characterized using ab initio simulations in terms of their donor levels, their local vibrational modes, the defect induced modifications of the electronic band structure, and the transition amplitudes at band edges. We have found that the so called I 3 -V is the most likely candidate for W PL center. It has a donor level and local vibrational modes in better agreement with experiments, a lower formation energy, and stronger transition amplitudes than the so called I 3 -I, which was previously proposed as W center. With respect to defect candidates to X PL center, our calculations have shown that none of analyzed defect candidates match all of the experimental characteristics of the X center. Although the Arai tetra-interstitial configuration previously proposed as X center cannot be excluded, the other defect candidates to X center found, I 3 -C and I 3 -X, cannot either being discarded.

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Influence of Ge content on the optical properties ofXandWcenters in dilute Si-Ge alloys

Cited by 17 publications

References 65 publications

Electron and Proton Irradiation of Silicon

Electron and Proton Irradiation of Silicon

Substrate and Mg doping effects in GaAs nanowires

Insights on the atomistic origin of X and W photoluminescence lines inc-Si fromab initiosimulations

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