Emission channeling studies of Li in semiconductors

Wahl, Ulrich

doi:10.1016/s0370-1573(96)00021-x

Cited by 50 publications

(39 citation statements)

References 79 publications

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“…This is a common trapping mechanism of diffusing interstitial impurities in semiconductors (quantitative models have been described in Ref. 29 for implanted 8 Li). In thermal equilibrium the fraction of interstitial Mg f i (T ) at a given temperature T is given by…”

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confidence: 99%

Precise lattice location of substitutional and interstitial Mg in AlN

Amorim

Wahl

Pereira

et al. 2013

Applied Physics Letters

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The lattice site location of radioactive 27Mg implanted in AlN was determined by means of emission channeling. The majority of the 27Mg was found to substitute for Al, yet significant fractions (up to 33%) were also identified close to the octahedral interstitial site. The activation energy for interstitial Mg diffusion is estimated to be between 1.1 eV and 1.7 eV. Substitutional Mg is shown to occupy ideal Al sites within a 0.1 Å experimental uncertainty. We discuss the absence of significant displacements from ideal Al sites, in the context of the current debate, on Mg doped nitride semiconductors.

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confidence: 99%

Precise lattice location of substitutional and interstitial Mg in AlN

Amorim

Wahl

Pereira

et al. 2013

Applied Physics Letters

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“…In order to extract correct lattice location information, the characteristic properties of the zinc blende structure have to be taken into account [14,17]. For instance, the <111> patterns do not allow one to discriminate S from T sites.…”

Section: Resultsmentioning

confidence: 99%

Emission channeling studies of implanted 167mEr in InP

Wahl

Vantomme

Langouche

et al. 2001

Nuclear Instruments and Methods in Physics Research Section B:

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We have used conversion electron emission channeling to determine the lattice location of 167m Er (t 1/2 =2.28 s) in InP after 60 keV room temperature implantation of 167 Tm (t 1/2 =9.25 d) at a dose of 6.8×10 12 cm -2 . Following annealing at temperatures above the major recovery step of the implantation damage at 100-150°C, we observe around 75% of Er on substitutional In sites. A smaller fraction of Er (7%) is found on substitutional P sites, the remainder on random sites. Annealing the unprotected InP crystal at temperatures above 250°C in vacuum causes a decrease in the channeling effects. Introduction Erbium doped InP shows luminescence at a wavelength of 1.54 µm [1-9], which is an interesting feature for infrared optoelectronic devices. Incorporation of Er in InP has been reported from both ion implantation [1][2][3][4][5][6][7][8] and doping during growth by metalorganic vapour phase epitaxy (MOVPE) [9]. An interesting aspect of the InP:Er system is the fact that its electroluminescence (EL) intensity is thermally stable and only slightly quenched at room temperature. This is in contrast to, e.g., the photo-and electroluminescence of Er in Si, but also to the Er photoluminescence (PL) in InP itself [3,4]. In order to explain this behaviour, it has been suggested that Er can exist in different configurations in InP. The absence of pronounced EL quenching was attributed to Er atoms occupying sites where they can be effectively excited via direct electron impact. On the other hand, the PL should be mainly caused by Er centers which are excited less efficiently by electron-hole recombination processes [3,4]. In that respect it is interesting to study possible lattice sites of implanted Er in InP. Substitutional In sites have been considered theoretically and are assumed to be the most likely occupied lattice positions of rare earth atoms in the 3+ ionization state [10]. Among the various rare earth doped InP systems only the lattice site of implanted Yb has been investigated previously by direct lattice location methods. Using the Rutherford backscattering (RBS) channeling technique, a 50% reduction in the backscattering yield of Yb was observed along the <100> direction [5][6][7][8]. However, the investigation of the axial <100> channeling alone does not allow one to discriminate, for instance, substitutional from tetrahedral interstitial sites or provide sublattice sensitivity and hence is not sufficient to unambiguously derive the lattice location.In order to carry out detailed lattice location studies of implanted Er in InP, we have applied conversion electron emission channeling [11] from the short-lived isotope

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“…A very good report of such type of work is presented in ref. [57], where alpha particles emitted from the decay of the short lived 8 Li are used to perform detailed lattice location studies of Li in elemental and compound semiconductors, to fluences even below 10 12 cm -2 .…”

Section: Emission Channelingmentioning

confidence: 99%

“…This is mainly due to the well-known 57* Fe (14.4 keV, 98 ns) isomeric state, i.e., an optimum case to be resonantly excited from decay of the long-lived 57 Co (271 d) gamma-ray source. The fact that 2.2% of the isotopic composition of natural iron is made of 57 Fe, further guarantees that 57 Fe/ 57 Co Mössbauer experiments remain preponderant in applied materials research.…”

Section: -Mössbauer Effectmentioning

confidence: 99%

“…In 1996, the technique received a considerable boost with the introduction of Mn laser ionisation sources at ISOLDE which made it possible to obtain high-intensity isotopically clean beams of the short-lived (1.5 min) 57 Mn that decays into the well-known 57 sites. However, from these data alone, it was not possible to determine whether ferromagnetism or paramagnetism was responsible for the observed magnetic sextet [100].…”

Section: F(ω)mentioning

confidence: 99%

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