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H. Wolf 1 , F. Wagner 1 , J. Kronenberg 1 , H. Wolf 1 , Th. Wichert 1 , K. Johnston 1

Diffusion behaviour of short lived isotopes in II‑VI semiconductors. H. Wolf 1 , F. Wagner 1 , J. Kronenberg 1 , H. Wolf 1 , Th. Wichert 1 , K. Johnston 1 and the ISOLDE Collaboration. 1) Technische Physik, Universität des Saarlandes, D-66123 Saarbrücken, Germany.

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H. Wolf 1 , F. Wagner 1 , J. Kronenberg 1 , H. Wolf 1 , Th. Wichert 1 , K. Johnston 1

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  1. Diffusion behaviour of short lived isotopes in II‑VI semiconductors H. Wolf1, F. Wagner1, J. Kronenberg1, H. Wolf1,Th. Wichert1, K. Johnston1 and the ISOLDE Collaboration 1) Technische Physik, Universität des Saarlandes, D-66123 Saarbrücken, Germany Supported by the BMBF, contract 05 KK7TS1

  2. Workshop 2006 Ag in CdTe: 828K, 60 min Ag in CdTe: 550K, 30 min vacuum Cd atmosphere • Up hill diffusion • Not explainable by fick´s laws H. Wolf, F. Wagner, Th. Wichert, Phys. Rev. Lett. 94, 125901 (2005)

  3. radiotracer technique 30 nm 111Ag annealing CdTe 111Ag 111Ag 500 K - 1000 K 0.5 – 0.8 mm

  4. radiotracer technique

  5. Workshop 2006 Ag in CdTe: 828K, 60 min Up hill diffusion What can we learn?

  6. Workshop 2007 • Interstitial Cd • Donator (Cdi++) • Substitutionell Ag • Acceptor (AgCd-) Cd Te • Interstitial Ag • Donator (Agi+) • Cd vacancy • Acceptor (VCd--)

  7. Cdi Cdi Workshop 2007 • Cd-atmosphere (828 K 60 min) • Cd-atmosphere: Cdi in diffusion •  [ΔC] = [Cdi]-[VCd] • [ΔC] determines µF • [Ag] = [Agi+] • Agi+ behaves like h+ • Ag profile reflect µF und [ΔC] [ΔCini]

  8. Workshop 2007 Ag in CdTe: 828K, 60 min Information about:  Diffusion coefficients  Formation energies  Ionizations energies

  9. II-VI semiconductors

  10. Ag in different semiconductors CdTe Cd0.96Zn0.04Te ZnTe 828K, 60 min 828K, 60 min 928K, 24 h Cd atmosphere Cd atmosphere Zn atmosphere Comparable behavior of Ag in different II-VI semiconductors

  11. Comparison Ag and Cu in CdTe Cd atmosphere, 828 K, 60 min Cu Ag concentration [cm-3] depth [µm] depth [µm] Comparable behavior of Ag and Cu

  12. Au diffusion in CdZnTe CdZnTe: 828K, 60 min, Cd atmosphere Pre anneal: 928K, Te atmosphere  D(Au) >> D(Teramoto et al.)  1µm  No uphil diffusion? I. Teramoto and S. Takayanagi, J. Phys. Soc. Jpn. 17 (1962) 1137.

  13. Cdi Cdi Au diffusion in CdZnTe [ΔCini]

  14. Au diffusion in CdZnTe CdZnTe: 828K, 60 min, Cd atmosphere Pre anneal: 928K, Te atmosphere  Up hill diffusion can be observed for Au [ΔCini] < 0 (VCd--)

  15. Na diffusion in CdTe Na: 750 K Na diffusion show up hill diffusion

  16. K diffusion in CdTe n p n p K: 750K Ag: 828K Weak penetration of K  diffusion in n-type part  no peak-shaped profile

  17. K, Mn and Fe diffuses to slow

  18. Co diffusion in CdZnTe CdZnTe Co: 800 K • Co diffusion enhanced by Cd atmosphere •  Box shaped Co profile

  19. n p n p Co diffusion in CdZnTe Co: 800 K Ag: 828 K Te rich (p-type): low mobility incorporation as CoCd ? Cd rich (n-type): high mobility Co present as Coi Coi negatively charged ?

  20. Ni diffusion in CdZnTe CdZnTe n p Ni: 800K Ni diffusion behaves similar to Co diffusion

  21. Summary • Up hill diffusion for different elements • Up hill diffusion in different semiconductors

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