Fe photoionization transition in ZnSSe:Fe crystals - photo-ESR studies
|Krzysztof Swiatek 2, Marek Godlewski 2,3, Tanya Surkova 1|
1. Russian Academy of Sciences, Ural Division, Institute of Metal Physics, 18 S.Kovalevskaya str., GSP-170, Ekaterinburg 620219, Russian Federation
Charge transfer processes in transition metal ions, which are doped in wide band-gap II-VI semiconductors, are of great interest because of possible application for novel optical and spintronic devices. In this work we study 2+ -> 3+ photoionization transition (PT) of iron ions in ZnSSe:Fe bulk crystals in temperature range of 2 - 100 K. By monitoring changes of the Fe3+ ESR (electron spin resonance) signal under external illumination we are able to determine energies of Fe2+ -> Fe3+ + eCB transition in different ZnSSe host crystals. At low temperature we observe metastable (in part) population of photo-excited Fe3+ centers. Free electrons created in the conduction band under the 2+ to 3+ ionization of iron, are efficiently trapped by donor centers. We observe also appropriate photoionization bands in low temperature absorption spectra. Previous studies have shown that the iron PT is an efficient channel for excitation of the Fe2+ intra-ion emission in ZnS:Fe at low temperature.
Presentation: poster at E-MRS Fall Meeting 2004, Symposium F, by Krzysztof Swiatek
See On-line Journal of E-MRS Fall Meeting 2004
Submitted: 2004-04-30 22:47 Revised: 2009-06-08 12:55