Position-sensitive Si pad detectors for electron emission channeling experiments

Wahl, Ulrich; Correia, J. G.; Czermak, A.; Jahn, S.G.; Jałocha, P.; Marques, J.G.; Rudge, A.; Schopper, F.; Soares, J. C.; Vantomme, André; Weilhammer, P.

doi:10.1016/j.nima.2003.12.044

Cited by 59 publications

(65 citation statements)

References 40 publications

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“…The emitted ␤ − particles and conversion electrons at room temperature were observed with a two-dimensional electron detector setup. 21,22 For lattice location studies both the ␤ − particles in the energy range above 95 keV as well as the 45.9 keV K-conversion electrons of 147 Pm emitted in the decay, 147 Nd→ 147 Pm were used for lattice location studies of 147 Nd and 147 Pm respectively. These charged particles are recorded simultaneously, and discrimination is possible by choosing appropriate energy windows in the later analysis.…”

Section: Methodsmentioning

confidence: 99%

Crystal field analysis ofPm3+(4f4)andSm3

et al. 2006

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We report a detailed crystal field analysis of Pm 3+ and Sm 3+ as well as lattice location studies of 147 Pm and 147 Nd in 2H-aluminum nitride ͑w-AlN͒. The isotopes of mass 147 were produced by nuclear fission and implanted at an energy of 60 keV. The decay chain of interest in this work is 147 Nd→ 147 Pm→ 147 Sm ͑stable͒. Lattice location studies applying the emission channeling technique were carried out using the ␤ − particles and conversion electrons emitted in the radioactive decay of 147 Nd→ 147 Pm. The samples were investigated as implanted, and also they were investigated after annealing to temperatures of 873 K as well as 1373 K. The main fraction of about 60% of both 147 Pm as well as 147 Nd atoms was located on substitutional Al sites in the AlN lattice; the remainder of the ions were located randomly within the AlN lattice. Following radioactive decay of 147 Nd, the cathodoluminescence spectra of Pm 3+ and Sm 3+ were obtained between 500 nm and 1050 nm at sample temperatures between 12 K and 300 K. High-resolution emission spectra, representing intra-4f electron transitions, were analyzed to establish the crystal-field splitting of the energy levels of Sm 3+ ͑4f 5 ͒ and Pm 3+ ͑4f 4 ͒ in cationic sites having C 3v symmetry in the AlN lattice. Using crystal-field splitting models, we obtained a rms deviation of 6 cm −1 between 31 calculated-to-experimental energy ͑Stark͒ levels for Sm 3+ in AlN. The results are similar to those reported for Sm 3+ implanted into GaN. Using a set of crystal-field splitting parameters B nm , for Pm 3+ derived from the present Sm 3+ analysis, we calculated the splitting for the 5 F 1 , 5 I 4 , and 5 I 5 multiplet manifolds in Pm 3+ and obtained good agreement between the calculated and the experimental Stark levels. Temperature-dependent lifetime measurements are also reported for the emitting levels 4 F 5/2 ͑Sm 3+ ͒ and 5 F 1 ͑Pm 3+ ͒.

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Section: Methodsmentioning

confidence: 99%

Crystal field analysis ofPm3+(4f4)andSm3

et al. 2006

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“…The angular emission patterns of the 42.3 keV and 52.1 keV conversion electrons from the 73 As ! 73 Ge decay were recorded around the 0001 , 1102 , 1101 , and 2113 directions by means of a position-sensitive Si detector [23]. These measurements were carried out at room temperature in the as-implanted state and following 10 min in situ vacuum annealing steps at 300 C, 600 C, and 900 C.…”

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confidence: 99%

“…[23]. In the fit procedure, we considered theoretical patterns resulting from emitter atoms at substitutional Zn sites (S Zn ) and O sites (S O ) with varying rms displacements, the main interstitial sites (cf.…”

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Direct Evidence for As as a Zn-Site Impurity in ZnO

et al. 2005

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Arsenic has been reported in the literature as one of the few p-type dopants in the technologically promising II-VI semiconductor ZnO. However, there is an ongoing debate whether the p-type character is due to As simply replacing O atoms or to the formation of more complicated defect complexes, possibly involving As on Zn sites. We have determined the lattice location of implanted As in ZnO by means of conversion-electron emission channeling from radioactive 73 As. In contrast to what one might expect from its nature as a group V element, we find that As does not occupy substitutional O sites but in its large majority substitutional Zn sites. Arsenic in ZnO (and probably also in GaN) is thus an interesting example for an impurity in a semiconductor where the major impurity lattice site is determined by atomic size and electronegativity rather than its position in the periodic system.

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“…24 Angular-dependent emission yields of the β − particles emitted during decay to stable 56 Fe were measured at room temperature, along four crystallographic directions, [0001], [1102], [1101] and [2113], in the asimplanted state and after in situ capless annealing in vacuum (< 10 −5 mbar) at 300 • C, 600 • C, 700 • C, 800 • C and 900 • C. The patterns were recorded using a positionand energy-sensitive detection system similar to that described in Ref. 25. Given the short half-life of 56 Mn, this system was installed on-line and upgraded with selftriggering readout chips for the Si pad detectors, enabling measurements during and/or immediately after implantation with count rates of up to several kHz.…”

Section: Methodsmentioning

confidence: 99%

Evidence of N substitution by Mn in GaN

et al. 2012

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We report on the lattice location of Mn in wurtzite GaN using β − emission channeling. In addition to the majority substituting for Ga, we locate up to 20% of the Mn atoms in N sites. We propose that the incorporation of Mn in N sites is enabled under sufficiently high concentrations of N vacancies, and stabilized by a highly charged state of the Mn cations. Since N substitution by Mn impurities in wurtzite GaN has never been observed experimentally or even considered theoretically before, it challenges the current paradigm of transition metal incorporation in wide-gap dilute magnetic semiconductors.

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Position-sensitive Si pad detectors for electron emission channeling experiments

Cited by 59 publications

References 40 publications

Crystal field analysis ofPm3+(4f4)andSm3

Crystal field analysis ofPm3+(4f4)andSm3

Direct Evidence for As as a Zn-Site Impurity in ZnO

Evidence of N substitution by Mn in GaN

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