Recombination processes in Yb-activated ZnS

Przybylińska, H.; Świątek, K.; Stapor, A.; Suchocki, A.; Godlewski, M.

doi:10.1103/physrevb.40.1748

Cited by 42 publications

(19 citation statements)

References 30 publications

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“…The energies of appropriate PI (charge transfer) transitions calculated basing on the concepts of Jorgensen's RESPET model [1,4] coincide very well with the experimental values [5][6][7]. In this model, after correction for multiplet splitting (ΔΕΜC) of the initial and final states, the ionization energy depends linearly on " q'', i.e.…”

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confidence: 48%

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Ionization Energies of RE Ions in wide Bandgap Sulphides

Świątek

Godlewskl

1991

Acta Phys. Pol. A

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The cucial point in selecting appropriate host materials and dopants for electroluminescent devices is the knowledge of the ionization energies of impurity ions from which an efficient emission may be obtained. RE ions represent a relatively simple system of dopants in wide bandgap materials. Due to the screening of the 4fq shell by the external 5s and 5p shells, all electronic and magnetic properties are either identical or close to those of free ions, and depend rather weakly on lattice ionicity, lattice parameters, and stucture. It was carefully tested that the energies of intra-ion and ionization transitions of a given RE ion are similar or nearly identical in crystals with the same ligand and independent of lattice "details" [1,2].Recently, we have shown that for Eu, Tm, and Yb the RE 2 +/3+ energy level is located in the forbidden gap of ZnS [3]. The energies of appropriate PI (charge transfer) transitions calculated basing on the concepts of Jorgensen's RESPET model [1,4] coincide very well with the experimental values [5][6][7]. In this model, after correction for multiplet splitting (ΔΕΜC) of the initial and final states, the ionization energy depends linearly on " q'', i.e. on the number of electrons on the 4f shell of the RE ion. ΔΕΜC can be easily calculated since the appropriate Racah and Lande parameters were given by Carnall et al. [8]. The linear term (E -A) in q approximates three important contributions to RE ionization energy:-the regular Z-and q-dependent increase due to the contraction of the RE ionic radius, *This work was supported by CPBP 01.12.(247)

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confidence: 48%

“…From the photoEPR experiments we know the positions of Eu 2 +/3 + and Yb2+/3+ energy levels in ZnS [5,7]. In our previous work [3] we have shown that the maximum around 26000 cm-1 in the excitation spectum of the Tm3 + 1G4 3H6 emission in ZnS, observed by Zimmermann and Boyn [6], should be attributed to Τm3 + + hv ÞTm2 + + hvb PI transition.…”

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confidence: 98%

Ionization Energies of RE Ions in wide Bandgap Sulphides

Świątek

Godlewskl

1991

Acta Phys. Pol. A

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“…In order to consider possible quenching models, it is necessary to first discuss the excitation mechanism. The most widely accepted model for energy transfer between the semiconductor host and the rare-earth ion was first discussed for II-VI compounds 19,20 and InP:Yb, 21,22 followed by a similar model for GaAs:Er. 18,23 In this model, the rare-earth ion introduces either an electron trap below the conduction band or a hole trap above the valence band.…”

Section: Thermal Quenching Propertiesmentioning

confidence: 99%

Photoluminescence studies of erbium-doped GaAs under hydrostatic pressure

Culp

Hömmerich

Redwing

et al. 1997

Journal of Applied Physics

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The photoluminescence properties of metal-organic chemical vapor deposition GaAs:Er were investigated as a function of temperature and applied hydrostatic pressure. The 4 I 13/2 → 4 I 15/2 Er 3ϩ emission energy was largely independent of pressures up to 56 kbar and temperatures between 12 and 300 K. Furthermore, no significant change in the low temperature emission intensity was observed at pressures up to and beyond the ⌫-X crossover at ϳ41 kbar. In contrast, Al x Ga 1Ϫx As:Er alloying studies have shown a strong increase in intensity near the ⌫-X crossover at xϳ0.4. These results suggest that the enhancement is most likely due to a chemical effect related to the presence of Al, such as residual oxygen incorporation, rather than a band structure effect related to the indirect band gap or larger band gap energy. Modeling the temperature dependence of the 1.54 m Er 3ϩ emission intensity and lifetime at ambient pressure suggested two dominant quenching mechanisms. At temperatures below approximately 150 K, thermal quenching is dominated by a ϳ13 meV activation energy process which prevents Er 3ϩ excitation, reducing the intensity, but does not affect the Er 3ϩ ion once it is excited, leaving the lifetime unchanged. At higher temperatures, thermal quenching is governed by a ϳ115 meV activation energy process which deactivates the excited Er 3ϩ ion, quenching both the intensity and lifetime. At 42 kbar, the low activation energy process was largely unaffected, whereas the higher activation energy process was significantly reduced. These processes are proposed to be thermal dissociation of the Er-bound exciton, and energy back transfer, respectively. A model is presented in which the Er-related electron trap shifts up in energy at higher pressure, increasing the activation energy to back transfer, but not affecting thermal dissociation of the bound exciton through hole emission. © 1997 American Institute of Physics. ͓S0021-8979͑97͒03912-1͔

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“…Such direct radiative recombination of the rare earth bound exciton was observed in few cases only [9][10][11]. The PL(T) measurements showed in fact a new PL band at increased temperature, whose appearance might be correlated with the decay of the 4f-4f PL of Yb 3 + [12].…”

Section: Resultsmentioning

confidence: 93%