1 / 25

Investigation of Short-Lived Isotope Diffusion in II-VI Semiconductors with Radiotracer Techniques

This study explores the diffusion behavior of short-lived isotopes, particularly silver (Ag), in II-VI semiconductors such as CdTe and CdZnTe. Conducted at the Universität des Saarlandes and supported by the BMBF, the research examines notable phenomena like "uphill diffusion", which deviates from traditional Fick's laws. Through annealing and radiotracer techniques, diffusion coefficients, formation energies, and ionization energies are analyzed across various conditions (e.g., Cd and Zn atmospheres). Findings contribute to the understanding of elemental behavior in semiconductor materials.

leontyne
Télécharger la présentation

Investigation of Short-Lived Isotope Diffusion in II-VI Semiconductors with Radiotracer Techniques

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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

More Related