| 1. |
- Enlund, Johannes, et al.
(författare)
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Anisotropic dry etching of boron doped single crystal CVD diamond
- 2005
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Ingår i: Carbon. - : Elsevier BV. - 0008-6223 .- 1873-3891. ; 43:9, s. 1839-1842
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Tidskriftsartikel (refereegranskat)abstract
- Semiconducting boron doped single-crystal CVD diamond has been patterned using aluminum masks and an inductively coupled plasma (ICP) etch system. For comparison insulating HPHT diamond samples were also patterned using the same process. Diamond etch rates above 200 nm/min were obtained with an O2/Ar discharge for a gas pressure of 2.5 mTorr using 600 W RF power. We have accomplished the fabrication of structures with a minimum feature size of 1 μm with vertical sidewalls in both CVD and HPHT diamond. The ICP etching produced smooth surfaces with a typical root-mean-square surface roughness of 3 nm. The dependence of etch rate on bias voltage was somewhat different for the two types of diamond. However, for all samples both the etch rate and anisotropy were found to improve with increasing bias voltage.
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| 2. |
- Isberg, Jan, et al.
(författare)
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Generation, transport and detection of valley-polarized electrons in diamond
- 2013
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Ingår i: Nature Materials. - 1476-1122 .- 1476-4660. ; 12:8, s. 760-764
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Tidskriftsartikel (refereegranskat)abstract
- Standard electronic devices encode bits of information by controlling the amount of electric charge in the circuits. Alternatively, it is possible to make devices that rely on other properties of electrons than their charge. For example, spintronic devices make use of the electron spin angular momentum as a carrier of information. A new concept is valleytronics in which information is encoded by the valley quantum number of the electron. The analogy between the valley and spin degrees of freedom also implies the possibility of valley-based quantum computing. In this Article, we demonstrate for the first time generation, transport ( across macroscopic distances) and detection of valley-polarized electrons in bulk diamond with a relaxation time of 300 ns at 77 K. We anticipate that these results will form the basis for the development of integrated valleytronic devices.
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| 3. |
- Isberg, Jan, et al.
(författare)
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Photoionization measurement of deep defects in single-crystalline CVD diamond using the transient-current technique
- 2006
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 73:24
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Tidskriftsartikel (refereegranskat)abstract
- We have adopted the transient-current technique as a sensitive method to detect small concentrations of charged defects in diamond and to study its photoionization spectrum. It is found that ionized impurity concentrations in the interval 10(9)-10(13) cm(-3) can readily be detected in diamond. By continuously measuring the charge concentration, while illuminating the samples with monochromatic light, the evolution of the charge state of the dominating defect can be continuously monitored. We have obtained the photoionization cross-section spectrum from the dominant deep defect in single-crystalline chemical vapor deposition (CVD) diamond using this method. The photoionization spectrum exhibits an onset at photon energies above E-i=2.2 eV. It is also found that the defect is in the positively charged and acts as an electron trap. The observed spectrum can be attributed to the single substitutional nitrogen impurity.
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| 4. |
- Suntornwipat, Nattakarn, et al.
(författare)
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A Valleytronic Diamond Transistor : Electrostatic Control of Valley Currents and Charge-State Manipulation of NV Centers
- 2021
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Ingår i: Nano letters (Print). - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 21:1, s. 868-874
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Tidskriftsartikel (refereegranskat)abstract
- The valley degree of freedom in many-valley semiconductors provides a new paradigm for storing and processing information in valleytronic and quantum-computing applications. Achieving practical devices requires all-electric control of long-lived valley-polarized states, without the use of strong external magnetic fields. Because of the extreme strength of the carbon–carbon bond, diamond possesses exceptionally stable valley states that provide a useful platform for valleytronic devices. Using ultrapure single-crystalline diamond, we demonstrate electrostatic control of valley currents in a dual-gate field-effect transistor, where the electrons are generated with a short ultraviolet pulse. The charge current and the valley current measured at the receiving electrodes are controlled separately by varying the gate voltages. We propose a model to interpret experimental data, based on drift-diffusion equations coupled through rate terms, with the rates computed by microscopic Monte Carlo simulations. As an application, we demonstrate valley-current charge-state modulation of nitrogen-vacancy centers.
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| 5. |
- Suntornwipat, Nattakarn, et al.
(författare)
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Magnetotransport study of valley-polarized electrons in synthetic diamond
- 2016
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Ingår i: Physical Review B. - 2469-9950 .- 2469-9969. ; 94:3
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate that the highly stable valley-polarized electron states in ultrapure single-crystalline diamond allow for investigation of charge transport, magnetoresistivity, and determination of the dominant scattering mechanism. The Hall effect gives rise to nonisotropic contributions in the mobility tensor that were measured at a temperature of 70 K in a time-of-flight setup with an added magnetic field. The observations of the magnetotransport of valley-polarized electrons in diamond are compared with both Monte Carlo simulations and an analytical model based on the Boltzmann transport equation. We establish that acoustic phonon scattering is the dominant electron scattering mechanism at 70 K for each of the valley polarizations in the investigated samples.
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