Influence of Irradiation on Defect Spin Coherence in Silicon Carbide

Kasper, Christian; Klenkert, Daniel; Shang, Zhongxia; Simin, D.; Gottscholl, Andreas; Sperlich, Andreas; Kraus, Hannes; Schneider, Christof; Zhou, Shengqiang; Trupke, Michael; Kada, Wataru; Ohshima, Takeshi; Dyakonov, Vladimir; Astakhov, G. V.

doi:10.1103/physrevapplied.13.044054

Cited by 48 publications

(32 citation statements)

References 64 publications

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“…Figure 3(a) shows the relaxation of a pure quadrupole mode using the pulse sequence (L−T −M π 1 − L) to initialize in D 0 , and then make a projective measurement at time-delay T . This is the usual protocol used to measure the 'T 1 ' time [2] [19]. Consistent with previous reports, a single exponential decay is observed.…”

supporting

confidence: 89%

“…This is towards the short end of the T 1 values reported for V 2 − Si in natural 4H-SiC. Together with the relatively short spin-echo times, T 2 (SE) < 2 µs this suggests the defect density of the sample is relatively high N V ∼ 10 16 cm −3 in this sample [19], or the relatively high background n-type doping (n = 3 × 10 15 cm −3 ) may reduce the stability of the defects charge state. Treating the slow dipole decay as a dc-component, a single exponential fit yields T 1/e = 48 ± 7 µs ≈ T f .…”

mentioning

confidence: 63%

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Relaxation dynamics of spin- 32 silicon vacancies in 4H -SiC

Ramsay

Rossi

2020

Phys. Rev. B

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Room temperature optically detected magnetic resonance experiments on spin 3/2 V2 Silicon vacancies in 4H-SiC are reported. The ms = +1/2 ↔ −1/2 transition is accessed using a two microwave frequency excitation protocol. The ratio of the Rabi frequencies of the +3/2 ↔ +1/2 and +1/2 ↔ −1/2 transitions is measured to be (0.90 ± 0.02) √ 3/2. The deviation from √ 3/2 is attributed to small difference in g-factor for different magnetic dipole transitions. Whereas a spin-1/2 system is characterized by a single T1 time, we show that the spin 3/2 system has three distinct relaxation modes that can be preferentially excited and detected. Compared to model where relaxation is caused by fluctuating B-field, a relatively fast relaxation between ms = ±1/2 states is observed.The density matrix of a qubit is often decomposed into the identity and three Pauli spin-half matrices. The resulting Bloch-vector provides an intuitive picture of the spin-half dynamics, and the populations relax with a single spin-lifetime termed T 1 . A spin 3/2 system has four states, and is described by a 4x4 density-matrix. By extension, the relaxation of the four spin populations is described by three relaxation modes, characterized by three time constants. Furthermore, the 4x4 density matrix can be represented by a multipole expansion of the identity, x3 dipole (P), x5 quadrupole (D), and x7 octupole (F)modes providing a more intuitive representation of the spin-3/2 density-matrix.[1] This representation has advantages for understanding the spin-relaxation processes of S=3/2. For example, a dipole-like perturbation does not mix different order poles fixing the spin relaxation times such that T p = 3T d = 6T f , as recently discussed theoretically in the case of a fluctuating magnetic field acting on a silicon vacancy in SiC.[2] [3] An accessible spin 3/2 system for testing this prediction is the V2 silicon vacancy in 4H-SiC [2,4,5]. Recently, a number of groups have demonstrated that defects in SiC have optically accessible spins with coherence times on a par with diamond [5,6]. Unlike diamond, the manufacturing of SiC electronic devices is advanced. For example, n-and p-type doping can be routinely achieved and good quality SiO 2 films can be deposited or grown on the surface, enabling CMOS processing. Due to the large breakdown voltages of SiC diodes and transistors, SiC devices are increasingly used in power electronic applications relevant to electric trains, cars and power transmission. As such rapid improvement in materials and device quality is to be expected, and there is growing interest in SiC for quantum devices [7][8][9][10][11].In this letter, we report room temperature optically detected magnetic resonance (ODMR) experiments on an ensemble of V2 silicon vacancies in 4H-SiC. By using a two microwave frequency setup, the +1/2 ↔ −1/2 transition can be detected optically [2] [12]. Rabi oscillations of all three magnetic dipole allowed transitions are measured. The ratio of the Rabi frequencies is compared to the value of √ 3/2, expected f...

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supporting

confidence: 89%

mentioning

confidence: 63%

Relaxation dynamics of spin- 32 silicon vacancies in 4H -SiC

Ramsay

Rossi

2020

Phys. Rev. B

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“…The origin of this broadening is an important topic for further study, particularly for applications in sensing. A rough estimate of the density of active V Si , based on the estimated yield and SRIM calculations gives ~ 10 17 cm −3 , much higher than the expected density of ~ 10 16 cm −3 for the electron irradiated sample 41 .…”

Section: Resultsmentioning

confidence: 71%

“…In an attempt to improve the V Si emission brightness and reduce background emission, we cleaned the sample and annealed at 400 °C for 2 h. This anneal temperature is based on improvements shown in other studies, while keeping the temperature low enough to avoid converting V Si into other defects [39][40][41] . The cleaning consisted of Acetone/Isopropanol at 40 °C, Piranha (5:1 H 2 SO 4 :H 2 O 2 at 100 °C), 5:1:1 NH 4 OH:H 2 O 2 :H 2 O at 40 °C, and a 4 h soak in 1:1 49% HF:69% HNO 3 .…”

Section: Resultsmentioning

confidence: 99%

Arrays of Si vacancies in 4H-SiC produced by focused Li ion beam implantation

Pavunny

Yeats

Banks

et al. 2021

Sci Rep

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Point defects in SiC are an attractive platform for quantum information and sensing applications because they provide relatively long spin coherence times, optical spin initialization, and spin-dependent fluorescence readout in a fabrication-friendly semiconductor. The ability to precisely place these defects at the optimal location in a host material with nano-scale accuracy is desirable for integration of these quantum systems with traditional electronic and photonic structures. Here, we demonstrate the precise spatial patterning of arrays of silicon vacancy ($${V}_{Si}$$ V Si ) emitters in an epitaxial 4H-SiC (0001) layer through mask-less focused ion beam implantation of Li+. We characterize these arrays with high-resolution scanning confocal fluorescence microscopy on the Si-face, observing sharp emission lines primarily coming from the $${V1}^{{\prime}}$$ V 1 ′ zero-phonon line (ZPL). The implantation dose is varied over 3 orders of magnitude, leading to $${V}_{Si}$$ V Si densities from a few per implantation spot to thousands per spot, with a linear dependence between ZPL emission and implantation dose. Optically-detected magnetic resonance (ODMR) is also performed, confirming the presence of V2 $${V}_{Si}$$ V Si . Our investigation reveals scalable and reproducible defect generation.

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“…Qubits and single-photon emitters are realized by defect engineering. A long spin-coherence time at room temperature was observed for isolated single-point defects in ion-implanted SiC such as silicon vacancy (V Si ), di-vacancy, and a carbon anti-site defect [6][7][8]. Defect engineering is also used for local carrier lifetime control necessary for the optimization of the switching loss of 4H-SiC power bipolar junction transistors [9] and elimination of the bipolar degradation [10].…”

Section: Introductionmentioning

confidence: 99%

Depth Profile Analysis of Deep Level Defects in 4H-SiC Introduced by Radiation

et al. 2020

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Deep level defects created by implantation of light-helium and medium heavy carbon ions in the single ion regime and neutron irradiation in n-type 4H-SiC are characterized by the DLTS technique. Two deep levels with energies 0.4 eV (EH1) and 0.7 eV (EH3) below the conduction band minimum are created in either ion implanted and neutron irradiated material beside carbon vacancies (Z1/2). In our study, we analyze components of EH1 and EH3 deep levels based on their concentration depth profiles, in addition to (−3/=) and (=/−) transition levels of silicon vacancy. A higher EH3 deep level concentration compared to the EH1 deep level concentration and a slight shift of the EH3 concentration depth profile to larger depths indicate that an additional deep level contributes to the DLTS signal of the EH3 deep level, most probably the defect complex involving interstitials. We report on the introduction of metastable M-center by light/medium heavy ion implantation and neutron irradiation, previously reported in cases of proton and electron irradiation. Contribution of M-center to the EH1 concentration profile is presented.

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Influence of Irradiation on Defect Spin Coherence in Silicon Carbide

Cited by 48 publications

References 64 publications

Relaxation dynamics of spin- 32 silicon vacancies in 4H -SiC

Relaxation dynamics of spin- 32 silicon vacancies in 4H -SiC

Arrays of Si vacancies in 4H-SiC produced by focused Li ion beam implantation

Depth Profile Analysis of Deep Level Defects in 4H-SiC Introduced by Radiation

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