Tuning of electrical charging effects for ferromagnetic Mn-doped ZnO nanocrystals embedded into a SiO2 layer fabricated by KrF excimer laser irradiation

Sejoon Lee, Deuk Young Kim, Tae Won Kang, Hyung Koun Cho

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

The ZnMnO nanocrystals were formed by the laser irradiation of the sputter-deposited ZnMnO ultrathin layer using a 248 nm KrF excimer laser, and the size and density of the nanocrystals were observed to be controllable by modulations of either the energy density or the frequency of the irradiated pulsed-laser beam. Metal-oxide-semiconductor capacitors fabricated using ZnMnO nanocrystals clearly showed the electrical charging effect, and it was observed that the memory window depends on the size and density of nanocrystals. For measurements of the spontaneous magnetization, ZnMnO nanocrystals showed to have room-temperature ferromagnetism with Mr of ∼1.5 emu/ cm 3 and Hc 167 Oe. By using ferromagnetism in ZnMnO nanocrystals, tuning of the memory window was demonstrated. Namely, it was clearly observed that the flat-band voltage shift of ∼1.25 V can be modulated to be ∼0.8 V by applying the magnetic field. This is attributed to the modulation of probabilities for tunneling events due to the increased magnetoelectrical repulsion between spin-polarized carriers in ZnMnO dilute magnetic semiconductor nanocrystals and unpolarized carriers in p-Si under the magnetic field. These results suggest that ZnMnO nanocrystals can be used for spin-functional memory devices.

Original languageEnglish
Article number023711
JournalJournal of Applied Physics
Volume106
Issue number2
DOIs
StatePublished - 2009

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