Spin Properties in Mn2+ doped CdSe/CdS Core-Shell Seeded Nanorods
Joanna Dehnel a, Yahel Barak a, Efrat Lifshitz a
a Technion, Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Haifa, Israel
nanoGe Fall Meeting
Proceedings of nanoGe Fall Meeting19 (NGFM19)
#NCFun19. Fundamental Processes in Semiconductor Nanocrystals
Berlin, Germany, 2019 November 3rd - 8th
Organizers: Ivan Infante and Jonathan Owen
Poster, Joanna Dehnel, 428
Publication date: 18th July 2019

Investigation of spin interactions and spin dynamic processes in magnetically doped semiconductors nanocrystals (NCs) plays an important role in the development of new spin-based technologies. Recent advance in colloidal chemistry enabled the incorporation of magnetic ions into various nanostructures (core-shell NCs, dot in rods, platelets) and explored the influence of shape, size confinement and dopant concentration on the final magneto-optical properties of NCs.

Here we use optically detected magnetic resonance (ODMR) technique to study the spin- dependent process in wurtzite Mn2+ doped CdSe/CdS seeded nanorods (NRs).  In the ODMR method detection is based on change in the luminescence intensity arising from a magnetic resonance event in the excited state (when the magnetic resonance event, can be correlated either with a spin flip of resident carrier or of the Mn2+ ion or both). 

An ODMR spectrum of reference undoped CdSe/CdS NRs sample, consists of single, sharp resonant band while in case of Mn doped NRs the spectrum is more complex. The resonance spectrum present a broad envelope band superimpose by a manifold of several features. The experimental results were simulated using spin Hamiltonian: including Zeeman effect, electron-hole exchange interaction, energy of Mn2+–electron and Mn2+–hole exchange interactions (s,p–d interactions).

The ODMR methodology was further implemented to obtain spin dynamic information by recording the ODMR spectra at different microwave modulation frequencies and measured in-phase (θ=0°) and quadrature-phase (θ=90°) with respect to the microwave pulse. The results for the Mn doped NRs suggests that the ODMR spectrum overlap with two components with different behaviour.

Understanding the role of nanocrystal shape and crystalline anisotropy can have impact on tailoring the magnetism in doped semiconductror nanocrystals.

© Fundació Scito
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