Insights on the atomistic origin of X and W photoluminescence lines in<i>c</i>-Si from<i>ab initio</i>simulations

Santos, Iván; Aboy, María; López, Pedro; Marqués, Luis A.; Pelaz, Lourdes

doi:10.1088/0022-3727/49/7/075109

Cited by 13 publications

(21 citation statements)

References 39 publications

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“…Details for these calculations can be found in Ref. [26]. It is worthy to note that I 3 -I, considered by Carvalho et al as W center, has the highest formation energy among I 3 defects considered in our study, and thus, it is the most unstable.…”

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confidence: 72%

“…We resorted to ab initio simulations to determine if the I n selected from CMD simulations are compatible with radiative transitions of W and X centers. We used the vasp code [21,22] with PBE-PAW pseudopotentials [23,24] to characterize (i) the electronic band structure of defects, which shows whether a defect might favor or not radiative recombinations; (ii) the defect formation energy in order to obtain the defect levels within the energy band gap to relate them with experimental PL photon energies [25]; and (iii) the LVMs, which can be directly compared to the experimental values observed in PL spectra [26].…”

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confidence: 99%

“…Differences between I 2 -V and I 3 -V configurations are not evident in the selected projection. For more details see reference[26] Band structure modifications induced by (a) I 2 -V and (b) I 3 -V defects in their neutral charge state. Band structure of c-Si is also shown with red dashed lines for comparison.FIGURESList of TablesI Properties of I 3 -V, I 3 -I, I 3 -X and I 4 -A from Fig.…”

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confidence: 99%

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W and X Photoluminescence Centers in Crystalline Si: Chasing Candidates at Atomic Level Through Multiscale Simulations

Aboy

Santos

López

et al. 2018

Journal of Elec Materi

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We combined several atomistic techniques to identify the structure of defects responsible for X and W photoluminescence lines in crystalline Si. We used kinetic Monte Carlo simulations to reproduce irradiation and annealing conditions used in photoluminescence experiments. We found that W and X radiative centers are related to small Si self-interstitial clusters but they coexists with larger Si self-interstitials clusters that can act as non-radiative centers. We used molecular dynamics simulations to explore the many different configurations of small Si self-interstitial clusters, and select those with the symmetry compatible to W and X photoluminescence centers. Using ab initio simulations we calculated their formation energy, donor levels and energy of local vibrational modes. On the ba

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confidence: 72%

Section: About Here]mentioning

confidence: 99%

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confidence: 99%

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W and X Photoluminescence Centers in Crystalline Si: Chasing Candidates at Atomic Level Through Multiscale Simulations

Aboy

Santos

López

et al. 2018

Journal of Elec Materi

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“…The Si selfinterstitial configurations included in this study were taken from those reported in the literature [11]. For the I2 clusters, we have used CMD simulations to identify and characterize the most common configurations [12]. CMD simulations were performed with the parallel code LAMMPS [13] and the Tersoff potential in its third parametrization.…”

Section: B Simulation Proceduresmentioning

confidence: 99%

Evaluation of energy barriers for topological transitions of Si self-interstitial clusters by classical molecular dynamics and the kinetic activation-relaxation technique

López

Ruiz

Santos

et al. 2017

2017 Spanish Conference on Electron Devices (CDE)

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The modeling of self-interstitial defects evolution is key for process and device optimization. For a self-interstitial cluster of a given size, several configurations or topologies exist, but conventional models assume that the minimum energy one is instantaneously reached. The existence of significant energy barriers for configurational transitions may change the picture of defect evolution in non-equilibrium processes (such as ion implantation), and contribute to explain anomalous defect observations. In this work, we present a method to determine the energy barriers for topological transitions among small self-interstitial defects, which is applied to characterize the Si self-interstitial and the di-interstitial cluster. Keywords-silicon; self-interstitial cluster; configurational transition; energy barrier I. INTRODUCTION Self-interstitial defects are commonly formed in Si as a consequence of fabrication processes, and may range from small selfinterstitial clusters (I-clusters) to extended defects, such as rod-like defects and dislocation loops. For I-clusters several configurations have been reported, each one characterized by a specific topology and a formation enthalpy [1]. Traditional defect evolution models only consider the minimum energy configuration for each cluster size, by assuming that there are no barriers among them. These models successfully describe defect kinetics [2], but they fail to explain some experimental observations, like the growth of dislocation loops in shallow Ge implanted Si, without the previous formation of rod-like defects [3]. The relevance of higher energy I-clusters configurations depends to a large extent on the existence and height of energy barriers for configurational transitions. The Nudged Elastic Band Method (NEBM) can be used to calculate energy barriers in a static way, by considering the initial, final, and at least one intermediate position of all moving atoms. As a predefined atomic position along the pathway for a configurational transition is considered, calculated energy barriers may be overestimated, if the pathway followed is not the lowest energy one. Classical molecular dynamics (CMD) uses a semi-empirical potential to simulate the vibration and movements of atoms, can provide the energetic and topological description of I-clusters, and simulate their dynamics. However, the determination of energy barriers for configurational transitions with CMD may be very time consuming, as these transitions are usually infrequent events compared to the fast vibrational movement of atoms.

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“…It is believed to have a trigonal geometry 15 and be made up of interstitial silicon atoms [17][18][19] .…”

Section: Introductionmentioning

confidence: 99%

Optimization of photoluminescence from W centers in silicon-on-insulator

Buckley,

Tait,

Moody

et al. 2019

Preprint

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W centers are trigonal defects generated by self-ion implantation in silicon that exhibit photoluminescence at 1.218 µm. We have shown previously that they can be used in waveguide-integrated all-silicon light-emitting diodes (LEDs). Here we optimize the implant energy, fluence and anneal conditions to maximize the photoluminescence intensity for W centers implanted in silicon-on-insulator, a substrate suitable for waveguide-integrated devices. After optimization, we observe near two orders of magnitude improvement in photoluminescence intensity relative to the conditions with the stopping range of the implanted ions at the center of the silicon device layer. The previously demonstrated waveguide-integrated LED used implant conditions with the stopping range at the center of this layer. We further show that such light sources can be manufactured at the 300-mm scale by demonstrating photoluminescence of similar intensity from 300 mm silicon-on-insulator wafers. The luminescence uniformity across the entire wafer is within the measurement error.

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

Cited by 13 publications

References 39 publications

W and X Photoluminescence Centers in Crystalline Si: Chasing Candidates at Atomic Level Through Multiscale Simulations

W and X Photoluminescence Centers in Crystalline Si: Chasing Candidates at Atomic Level Through Multiscale Simulations

Evaluation of energy barriers for topological transitions of Si self-interstitial clusters by classical molecular dynamics and the kinetic activation-relaxation technique

Optimization of photoluminescence from W centers in silicon-on-insulator

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