Atomically controlled doping of nitrogen on GaAs(001) surfaces

Shimizu, N.; Inoue, T.; Wada, Osamu

doi:10.1016/j.jcrysgro.2006.11.092

Cited by 8 publications

(8 citation statements)

References 5 publications

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“…The N doping has been performed at 570°C on the GaAs buffer layer by confirming the N-stabilized ͑3 ϫ 3͒ long-range ordered surface. 4,14 During the N doping, the As shutter was not closed. Following the nitridation, a 50-nm-thick GaAs capping layer was grown.…”

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confidence: 99%

Fine structure splitting of isoelectronic bound excitons in nitrogen-doped GaAs

Harada

Wada

2008

Phys. Rev. B

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We have studied the fine structure polarization splitting of exciton emission lines related to isoelectronic centers in an nitrogen-doped GaAs. The nitrogen doping has been performed in atomically controlled way using the ͑3 ϫ 3͒ nitrogen stable surface of GaAs͑001͒, which forms a series of distinct, strong, narrow bandwidth luminescence lines. The localized bound excitons have been found to consist of four signals, which can be selected by linear polarization. Magnetic-field-induced change in the splitting shows a quadratic dependence of the bright exciton splitting owing to the in-plane Zeeman interaction. Our calculations of the optical selection characteristics considering both the J-J coupling and local-field effects demonstrate the polarization splitting depending on the symmetry of the isoelectronic center.Nitrogen ͑N͒ has a strong electronegativity and creates isoelectronic centers in III-V semiconductors such as GaAs and GaP. The electronic states created by the N-related centers cause substantial localization of excitons. Incorporation of a small amount of N atoms leads to dramatic changes in the local electronic structure of the host semiconductor. 1,2 In the impurity limit, the localized electronic states relating to N pairs and N clusters have been observed to show resolution-limited luminescence lines. 3,4 The extremely narrow bandwidth luminescence has been attracting strong interest for light sources such as single photons and eventready polarization entangled photon pairs utilized in quantum information processing. From the same point of view, the atomlike properties of single self-assembled semiconductor quantum dots ͑QDs͒ have been widely studied. 5-10 However, the emission energy is difficult to control and, furthermore, the exchange interactions in the in-plane asymmetries of the QD cause a significant fine structure splitting of the intermediate exciton states, which eventually gives rise to the so-called "which path" information. 9 In contrast to the self-assembled QDs, utilization of the impurity states in semiconductor materials can achieve a narrow bandwidth bound exciton emission with defined photon energy. Recently, each individual bound exciton has been demonstrated to be able to generate single photons. 11-13 Since the fine structure splitting of the impurity center is influenced by the electron-hole exchange interactions and the symmetry, understanding of the detailed structure of the polarization splitting and the interactions in the center is indispensable to control the fine structure.Here, we have studied the fine structure polarization splitting of exciton emission lines related to N pairs in GaAs. The in-plane Zeeman interaction causes a field evolution of the split states. To understand detailed exchange interactions in the centers, we performed calculations of the optical selection characteristics considering both the J-J coupling and local-field effects.N atomic-layer doped GaAs has been grown on an undoped GaAs͑001͒ substrate by molecular-beam epitaxy. Before doping N, a 3...

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confidence: 99%

Fine structure splitting of isoelectronic bound excitons in nitrogen-doped GaAs

Harada

Wada

2008

Phys. Rev. B

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“…This indicates that a N-stabilized reconstructed surface is formed by the substitution of N atoms for As atoms. 26,27 The N-sheet densities were estimated from the N-irradiation time dependence of the N-sheet density. The N-sheet densities (n s ), which were derived from the secondary ion mass spectroscopy (SIMS) profile shown in the inset, are plotted as a function of the N-irradiation time (t) in Fig.…”

Section: Methodsmentioning

confidence: 99%

“…In this paper, we propose a method for controlling the photoluminescence (PL) emission wavelength by growing InAs QDs on a N-d-doped GaAs. Such N-d doping was performed in an atomically controlled way using the N-stabilized surface on GaAs(001), 26,27 in which the active N species were supplied to the GaAs surface. The QDs grown on low-density N-d-doped GaAs exhibited a blueshifted emission with respect to those grown on undoped GaAs, and the emission wavelength was redshifted with increasing N-sheet density.…”

Section: Introductionmentioning

confidence: 99%

Emission-wavelength tuning of InAs quantum dots grown on nitrogen-δ-doped GaAs(001)

Kaizu

Taguchi

2016

Journal of Applied Physics

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We studied the structural and photoluminescence (PL) characteristics of InAs quantum dots (QDs) grown on nitrogen (N) d-doped GaAs(001). The emission wavelength for low-density N-d doping exhibited a blueshift with respect to that for undoped GaAs and was redshifted with increasing N-sheet density. This behavior corresponded to the variation in the In composition of the QDs. N-d doping has two opposite and competing effects on the incorporation of Ga atoms from the underlying layer into the QDs during the QD growth. One is the enhancement of Ga incorporation induced by the lattice strain, which is due to the smaller radius of N atoms. The other is an effect blocking for Ga incorporation, which is due to the large bonding energy of Ga-N or InN. At a low N-sheet density, the lattice-strain effect was dominant, while the blocking effect became larger with increasing N-sheet density. Therefore, the incorporation of Ga from the underlying layer depended on the N-sheet density. Since the In-Ga intermixing between the QDs and the GaAs cap layer during capping also depended on the size of the as-grown QDs, which was affected by the N-sheet density, the superposition of these three factors determined the composition of the QDs. In addition, the piezoelectric effect, which was induced with increased accumulation of lattice strain and the associated high In composition, also affected the PL properties of the QDs. As a result, tuning of the emission wavelength from 1.12 to 1.26 lm was achieved at room temperature.

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“…It is experimentally known that N atoms are substituted for matrix group V atoms to form N-pairs and act as isoeletctonic traps resulting in sharp luminescence lines [5]. Kita et al have developed a site-controlled N δdoping technique using molecular beam epitaxy (MBE) to study the fine structure splitting of excitons bound to the N-pair centers oriented along [110] in GaAs [6][7][8]. From theoretical viewpoints, Jenichen et al investigated stable subsurface lattice sites for N atoms on various GaAs(001) surfaces including c(4×4), (2×4)α1, (2×4)α2, (2×4)β1, (2×4)β2, and (4×2)ζ using density functional supercell calculations [9].…”

Section: Introductionmentioning

confidence: 99%

Ab initio-Based Approach to N-pair Formation on GaAs(001)-(2×4) Surfaces

Sugitani

Akiyama

et al. 2014

e-J. Surf. Sci. Nanotechnol.

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Nitrogen-pair formation processes on the GaAs(001)-(2×4) surfaces found experimentally are systematically investigated using ab initio-based approach incorporating beam equivalent pressure p (pAs = 3.0 × 10 −6 Torr, pN = 7.0 × 10 −6 Torr) and temperature T = 830 K. The calculated surface phase diagrams elucidates that the (2×4)α1 and (2×4)α2 surfaces are stable at the growth conditions under As2 and As4, respectively. The Monte Carlo simulations reveal that the N incorporation on the (2×4)α1 and (2×4)α2 surfaces proceeds with increase of energetically favorable Ga-N bonds in the third layer via series of events such as adsorption of N-As dimer, substitution of N for As located in the third layer, and As dimer desorption to form the N-pair in the third layer. It is also found that the probability of the N-pair formation on the (2×4)α1 surface is much larger than that on the (2×4)α2 surface. This is because the strain around the N-pair on the (2×4)α1 surface is smaller than that on the (2×4)α2 surface where N-As surface dimer is formed to relax the larger strain. Furthermore, the N-pair formation probabilities P under As2 and As4 are estimated as a function of temperature including (2×4)β1. N atoms incorporated on the GaAs(001) surface can form N-pair along [110] with P ∼ 0.8 on the surface with two phase mixture of (2×4)α1 and (2×4)α2 at T = 830 K under As2 and As4.

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Atomically controlled doping of nitrogen on GaAs(001) surfaces

Cited by 8 publications

References 5 publications

Fine structure splitting of isoelectronic bound excitons in nitrogen-doped GaAs

Fine structure splitting of isoelectronic bound excitons in nitrogen-doped GaAs

Emission-wavelength tuning of InAs quantum dots grown on nitrogen-δ-doped GaAs(001)

Ab initio-Based Approach to N-pair Formation on GaAs(001)-(2×4) Surfaces

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