We report on room-temperature electroluminescence from an all-inorganic light emitting device based on spin-coated ZnO nanoparticles. A tight submicron thick layer was fabricated on a fluorine doped tin oxide glass as a substrate using commercially available ZnO nanoparticles from the gas phase. After the evaporation of the top Al electrode, a diodelike I-V characteristic was obtained. An emission peak at around 390 nm and a broad defect-related electroluminescence in the visible range were observed at voltages below 10 V and ambient air conditions.

We demonstrate a method to electrically manipulate the spin polarization in a semiconductor on a micrometer length scale and a submicrosecond time scale. A variable magnetic field induced by a microscale current loop magnetizes the Mn2+ ions in a CdMnTe/CdMgTe diluted magnetic semiconductor quantum well, and via sp-d exchange interaction polarizes photogenerated electron-hole pairs. A maximum spin polarization degree of ±8.5% is obtained at 4.2 K without external magnetic field. The induced carrier spin polarization and the thermal heating of Mn2+ spins are resolved spatially and temporally by microphotoluminescence measurements.

We demonstrate that fringe fields stemming from nanostructured ferromagnets (FMs) provide the opportunity to manipulate spins in an underlying dilute magnetic semiconductor (DMS) heterostructure, both coherently and incoherently. Fringe fields from Fe/Tb FMs with a remanent out-of-plane magnetization induce a local out-of-plane magnetization in a ZnCdMnSe DMS. Due to the sp -d exchange interaction, optically generated electron -hole pairs align their spin along the DMS magnetization. We obtain a local, remanent spin polarization probed by both spatially resolved, polarization sensitive magneto-photoluminescence spectroscopy and Faraday rotation technique. Fringe fields from in-plane magnetized Co FMs allow us to modify the precession frequency of Manganese (Mn 2+ ) magnetic moments in an in-plane external magnetic field, which is directly probed by time-resolved Kerr rotation technique.

No abstract

We investigated a hybrid structure consisting of microstructured Fe/Tb multilayer ferromagnets (FMs) and a ZnCdMnSe dilute magnetic semiconductor quantum well (DMS QW) by means of superconducting quantum interference device (SQUID) magnetometry and micro-photoluminescence (µPL) spectroscopy. The Fe/Tb multilayers show a strong perpendicular magnetic anisotropy (PMA) with a temperature dependent coercive field H c reaching values of 2.5 T /µ0 at 4 K. The out-of-plane magnetic fringe field stemming from the Fe/Tb microstructures induces a locally varying magnetization in the underlying DMS QW, which polarizes the spins of optically excited charge carriers in the DMS. We demonstrate that the coupling between these magnetic systems enables us to control the local carrier spin polarization in the DMS via the magnetization of microscale Fe/Tb ferromagnetic wires.