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Baker, J M; Machi, I.Z.; Connell, S. H.; Bharuth‐Ram, K.; Butler, J. E.; Cox, S. F. J.; Fischer, Christoph; Jestädt, T; Murphy, P. G.; Nilen, R.W.N.; Sellschop, J.P.F.

doi:10.1023/a:1017098901501

Cited by 8 publications

(4 citation statements)

References 10 publications

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“…For extensive data tables, see Walker and Karolczak (2008). We mention simply a milestone test of reaction rate theory for Mu + H 2 and Mu + D 2 (Reid et al 1987) and articles by Connor (1981), Baer et al (1992), Walker (1985Walker ( , 1998, Roduner (1986aRoduner ( , 1988Roduner ( , 2006, Percival et al (2005). We can hardly include superheavy hydrogen amongst the isotopes here, 5 H, since its chemistry has yet to be studied (Korsheninnikov et al 2001)!…”

Section: µSr : Muon Spin Rotation Relaxation and Resonancementioning

confidence: 99%

“…B C Webster points out that a mere discrepancy in mass is not a sufficient condition for the separation of nuclear and electronic wavefunctions; he notes that a better criterion is the Virial theorem, finding that it is indeed satisfied in his calculations on model muoniated systems and that the natural electronic orbitals are identical for the different isotopomers. Baer et al (1992), Walker (1996Walker ( , 1998, Roduner (1986aRoduner ( , 1988Roduner ( , 2006, Percival et al (2005). (See also the data compendium by Karolczak (2008).…”

Section: Hyperfine and Structural Isotope Effects; Validity Of The Bo...mentioning

confidence: 99%

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Muonium as a model for interstitial hydrogen in the semiconducting and semimetallic elements

Cox

2009

Rep. Prog. Phys.

116

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Although the interstitial hydrogen atom would seem to be one of the simplest defect centres in any lattice, its solid state chemistry is in fact unknown in many materials, not least amongst the elements. In semiconductors, the realization that hydrogen can profoundly influence electronic properties even as a trace impurity has prompted its study by all available means-but still only in the functionally important or potentially important materials-for the elements, Si, Ge and diamond. Even here, it was not studies of hydrogen itself but of its pseudo-isotope, muonium, that first provided the much needed microscopic pictures of crystallographic site and local electronic structure-now comprehensively confirmed by ab initio computation and such data as exists for monatomic, interstitial hydrogen centres in Si. Muonium can be formed in a variety of neutral paramagnetic states when positive muons are implanted into non-metals. The simple trapped atom is commonly only metastable. It coexists with or reacts to give defect centres with the unpaired electron in somewhat more extended orbitals. Indications of complete delocalization into effective mass states are discussed for B, α-Sn, Bi and even Ge, but otherwise all the muonium centres seen in the elemental semiconductors are deep and relatively compact. These are revealed, distinguished and characterized by µSR spectroscopy-muon spin rotation and resonance informing on sites and spin-density distributions, muon spin relaxation on motional dynamics and charge-state transitions.This Report documents the progress of µSR studies for all the semiconductors and semimetals of the p-block elements, Groups III-VI of the Periodic Table . The striking spectra and originally unanticipated results for Group IV are for the most part well known but deserve summarizing and updating; the sheer diversity of muonium states found is still remarkable, especially in carbon allotropes. The interplay of crystallographic site and charge state in Si and Ge at high temperatures, or under illumination, reflects the capture and loss of charge carriers that should model the electrical activity of monatomic hydrogen but still challenges theoretical descriptions. Spin-flip scattering of conduction electrons by the paramagnetic centres is revealed in heavily doped n-type material, as well as some modification of the local electronic structures. The corresponding spectroscopy for the solid elements of Groups III, V and VI is rather less well known and is reviewed here for the first time; a good deal of previously unpublished data is also included. Theoretical expectations and computational modelling are sparse, here. Recent results for B suggest a relatively shallow centre with molecular character; P and As show deeper quasi-atomic states, but still with substantial overlap of spin density onto surrounding host atoms. Particular attention is paid to the chalcogens. Muonium centres in Te show charge-state transitions already around room temperature; the identification of those in S and Se has been compli...

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Section: µSr : Muon Spin Rotation Relaxation and Resonancementioning

confidence: 99%

Section: Hyperfine and Structural Isotope Effects; Validity Of The Bo...mentioning

confidence: 99%

Muonium as a model for interstitial hydrogen in the semiconducting and semimetallic elements

Cox

2009

Rep. Prog. Phys.

116

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“…Si [21,[50][51][52][53][54][55], a-Si [56][57][58], SiC [59,60], Ge [19,21,51,61,62] a-Ge [63] Si:Ge [31,[64][65][66], graphite [67], diamond [68][69][70][71]. Less functional p-block elements, but with equally intriguing chemical physics, illustrated in figure 16 for sulphur: α-Sn [48,72], B [48,73], P [48,74], As [48,74], S [48,49], Se [48,75], Te [48,76].…”

Section: Appendix Isis Muonics: Materials Studiedmentioning

confidence: 99%

The first 25 years of semiconductor muonics at ISIS, modelling the electrical activity of hydrogen in inorganic semiconductors and high-κdielectrics

et al. 2013

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Early muonium studies provided the very first atomistic pictures of interstitial hydrogen in semiconductors. By the time ISIS muons came on line, the main crystallographic sites, and the electronic structures for the neutral centres, were established in archetypal materials such as Si and GaAs. The results were quite unanticipated, and raised awareness of this deceptively simple defect system. This paper marks contributions to the subject made using ISIS muon beams, in the first 25 years of their operation since 1987. By this time, hydrogen was understood to be a significant and unavoidable impurity in all electronic grade material, and attention was turning to the interaction with charge carriers, revealing an equally unanticipated interplay of site and charge state. In particular, muonium spectroscopy now provides a model for hydrogen in dozens of materials where hydrogen itself is difficult or impossible to study directly, and is able to predict its effect on the electronic properties of new materials, such as those envisaged for optoeletronic or dielectric applications. Donor, acceptor and so-called pinning levels are known in a good many of these materials, revealing intriguing systematics and providing severe tests and challenges to current theory. Progress and prospects are summarized in this report, addressing the obvious questions such as ‘why, how and what next?’

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“…This turned out to be the case. In fact almost 100% recovery of the spin polarization was possible already at a field of 0.4 T for the extrapolated initial muon fraction [22][23][24]. The corresponding TF-"SR data for this sample were used to assist in extracting the components due to Mu T , Mu BC and " + from the net LF-"SR repolarisation curve.…”

Section: N-h Complexes -Possible Shallow Molecular Dopantsmentioning

confidence: 99%

MSR Studies in the Progress Towards Diamond Electronics

2005

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The recent development of device quality synthetic diamond dramatically increases the potential of diamond as a wide band gap semiconductor. A remaining obstacle is the lack of shallow n-type dopants. Molecular dopant systems have been shown theoretically to lead to the shallowing of levels in the band gap. Some of these systems involve defect-hydrogen complexes. This, and other phenomena, motivate the study of the chemistry and dynamics of hydrogen in diamond. Much information on this topic has been obtained from Muon Spin Rotation (MSR) experiments. These experiments view the muonium (Mu K " + e j ) atom as a light chemical analogue of hydrogen. Data on isolated muonium in diamond is reviewed, and evidence on formation of N-Mu-N (a shallow dopant candidate), the trapping of Mu at B-dopants, and fast quantum diffusion of muonium are discussed.

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Cited by 8 publications

References 10 publications

Muonium as a model for interstitial hydrogen in the semiconducting and semimetallic elements

Muonium as a model for interstitial hydrogen in the semiconducting and semimetallic elements

The first 25 years of semiconductor muonics at ISIS, modelling the electrical activity of hydrogen in inorganic semiconductors and high-κdielectrics

MSR Studies in the Progress Towards Diamond Electronics

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