Electrical Charge State Manipulation of Single Silicon Vacancies in a Silicon Carbide Quantum Optoelectronic Device

Widmann, Matthias; Niethammer, Matthias; Fedyanin, Dmitry Yu.; Khramtsov, Igor A.; Rendler, Torsten; Booker, Ian Don; Ul-Hassan, Jawad; Morioka, Naoya; Chen, Y. C.; Ivanov, Ivan Gueorguiev; Són, Nguyên Tiên; Ohshima, Takeshi; Bockstedte, Michel; Gali, Ádám; Bonato, Cristian; Lee, Sang-Yun; Wrachtrup, Jörg

doi:10.1021/acs.nanolett.9b02774

Cited by 81 publications

(76 citation statements)

References 64 publications

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“…22 Recently, electric field-dependent manipulation of single silicon vacancies was demonstrated using the intrinsic region of 4H-SiC p-i-n diodes. 51 In the intrinsic region, the Fermi level is close to the middle of the band gap, and switching may occur between the neutral and single negative charge state. In n-type material, on the other hand, the Fermi level is close to the conduction band with V Si predominantly in the 2À or 3À charge states.…”

Section: Discussionmentioning

confidence: 99%

Electrical charge state identification and control for the silicon vacancy in 4H-SiC

et al. 2019

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Reliable single-photon emission is crucial for realizing efficient spin-photon entanglement and scalable quantum information systems. The silicon vacancy (V Si) in 4H-SiC is a promising single-photon emitter exhibiting millisecond spin coherence times, but suffers from low photon counts, and only one charge state retains the desired spin and optical properties. Here, we demonstrate that emission from V Si defect ensembles can be enhanced by an order of magnitude via fabrication of Schottky barrier diodes, and sequentially modulated by almost 50% via application of external bias. Furthermore, we identify charge state transitions of V Si by correlating optical and electrical measurements, and realize selective population of the bright state. Finally, we reveal a pronounced Stark shift of 55 GHz for the V1′ emission line state of V Si at larger electric fields, providing a means to modify the single-photon emission. The approach presented herein paves the way towards obtaining complete control of, and drastically enhanced emission from, V Si defect ensembles in 4H-SiC highly suitable for quantum applications.

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Section: Discussionmentioning

confidence: 99%

Electrical charge state identification and control for the silicon vacancy in 4H-SiC

et al. 2019

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“…Particularly, silicon vacancies (V Si ) and siliconcarbon divacancies (VV) in SiC reveal extremely long spin coherence time [7,8,16,[20][21][22][23][24][25] and hold promise to implement quantum repeaters due to inherent spin-photon interface and high spectral stability [26][27][28][29][30]. Existing device fabrication protocols on the wafer scale in combination with threedimensional (3D) defect engineering [31][32][33] allow manufacturing integrated quantum devices [34][35][36][37] with electrical [38][39][40] and mechanical [39,41,42] control of defect spin qubits. SiC nanocrystals with color centers are also suggested as fluorescence biomarkers in biomedical applications [43,44].…”

Section: Introductionmentioning

confidence: 99%

Local vibrational modes of Si vacancy spin qubits in SiC

et al. 2020

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Silicon carbide is a very promising platform for quantum applications because of the extraordinary spin and optical properties of point defects in this technologically friendly material. These properties are strongly influenced by crystal vibrations, but the exact relationship between them and the behavior of spin qubits is not fully investigated. We uncover the local vibrational modes of the Si vacancy spin qubits in as-grown 4H-SiC. We apply microwave-assisted spectroscopy to isolate the contribution from one particular type of defects, the so-called V2 center, and observe the zero-phonon line together with seven equally separated phonon replicas. Furthermore, we present first-principles calculations of the photoluminescence line shape, which are in excellent agreement with our experimental data. To boost up the calculation accuracy and decrease the computation time, we extract the force constants using machine-learning algorithms. This allows us to identify the dominant modes in the lattice vibrations coupled to an excited electron during optical emission in the Si vacancy. A resonance phonon energy of 36 meV and a Debye-Waller factor of about 6% are obtained. We establish experimentally that the activation energy of the optically induced spin polarization is given by the local vibrational energy. Our findings give insight into the coupling of electronic states to vibrational modes in SiC spin qubits, which is essential to predict their spin, optical, mechanical, and thermal properties. The approach described can be applied to a large variety of spin defects with spectrally overlapped contributions in SiC as well as in other threeand two-dimensional materials.

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“…Recently, the 2− and 3− charge states were shown to be more stable than V − Si in n-type material, by correlating density functional theory (DFT) calculations to deep level transient spectroscopy (DLTS) measurements [9]. Indeed, substantial enhancement of emission from V Si ensembles [9] and control of the charge state of isolated V Si defects [15] was recently demonstrated via application of electric fields, and attributed to selective population of the bright and dark charge states.…”

Section: Introductionmentioning

confidence: 99%

Influence of hydrogen implantation on emission from the silicon vacancy in 4H-SiC

Bathen

Galeckas

Coutinho

et al. 2020

Journal of Applied Physics

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The silicon vacancy (V Si) in 4H-SiC is a room temperature single-photon emitter with a controllable high-spin ground state, and is a promising candidate for future quantum technologies. However, controlled defect formation remains a challenge, and recently it was shown that common formation methods such as proton irradiation may in fact lower the intensity of photoluminescence (PL) emission from V Si as compared to other ion species. Herein, we combine hybrid density functional calculations and PL studies of proton-irradiated n-type 4H-SiC material to explore the energetics and stability of hydrogen-related defects, situated both interstitially and in defect complexes with V Si , and confirm the stability of hydrogen in different interstitial and substitutional configurations. Indeed, V Si-H is energetically favorable if V Si is already present in the material, e.g., following irradiation or ion implantation. We demonstrate that hydrogen has a significant impact on electrical and optical properties of V Si , by altering the charge states suitable for quantum technology applications, and provide an estimate for the shift in thermodynamic transition levels. Furthermore, by correlating the theoretical predictions with PL measurements of 4H-SiC samples irradiated by protons at high (400 • C) and room temperatures, we associate the observed quenching of V Si emission in the case of high-temperature and highfluence proton irradiation with the increased mobility of H i , which may initiate V Si-H complex formation at temperatures above 400 • C. The important implication of hydrogen being present is that it obstructs formation of reliable and efficient single-photon emitters based on silicon vacancy defects in 4H-SiC.

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Electrical Charge State Manipulation of Single Silicon Vacancies in a Silicon Carbide Quantum Optoelectronic Device

Abstract: power which are fit parameters. At 0 V, =5.2±0.3 kcts and = 10±1 mW, and at -5V, = 2.0±0.3 kcts and = 0.90±0.01 mW.

Cited by 81 publications

References 64 publications

Electrical charge state identification and control for the silicon vacancy in 4H-SiC

Electrical charge state identification and control for the silicon vacancy in 4H-SiC

Local vibrational modes of Si vacancy spin qubits in SiC

Influence of hydrogen implantation on emission from the silicon vacancy in 4H-SiC

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