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NATO SfP-Novel Nanostructures Project 984735
Project description
Abstract of Research
The project deals with diluted magnetic nanostructures based on wurtzite semiconductors (mainly ZnO and GaN) to provide optimized devices for electronics and optoelectronics.
Theoretical part: using symmetry analysis and ab initio calculations it is tried to correlate the distribution of magnetic ions in the nanostructures with their magnetic properties.
Experimental part: we study
a) ZnO samples for UV detectors in the range of 0.38 micrometer. Conversely, the samples can also be used as spin-LEDs.
b) GaN samples for spin-filters (spintronics). Conversely, the samples can also be used as spin-modulators.
Major Objectives
- Correlate the direction of easy magnetization with distribution of magnetic atoms over the lattice.
- Increase the amount of magnetic atoms introduced into the semiconductor lattices.
- Create p-doped zones in GaN samples (probably by co-doping with Mg).
- Increase speed of UV detectors.
- Check the performances of the devices.
- Transfer obtained results to industry.
Staff
Equipment
Triple Raman-luminescence spectrometer system Horiba Jobin-Yvon T64000 (France)
- Optical range: 300 – 1700 nm;
- Spectral resolution: 0,15 cm-1;
- Three configurations are possible:
- triple additive mode with high spectral resolution (< 0.15 cm-1);
- triple substractive mode for low-frequency measurements (< 5 cm-1);
- single mode with high sensitivity.
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Confocal microscope UV-Visible-NIR Olympus BX41 (Japan)
Set of optical objectives:- MPlan N 10x/0.25 visible
- MPlan N 50x/0.75 visible
- MPlan N 100x/0.9 visible
- LMPlanFL N 50x/0.5 long working distance, visible
- HCX PL FLUOSTAR L 50x/0.55 long working distance, NIR
- LMU 40x NUV
- LMU 15x long working distance, NUV
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XYZ motorized stage (Marghauser SensoTech GmbH, Germany)
- computer-controled
- scanning step of 100 nm
- automated XYZ Raman and PL mapping
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Macrochamber with possibility to realize 90º scattering geometry
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CCD detectors for registration: Si (Andor), InGaAs (Horiba Jobin Yvon)
- CCD TE-1024x256, Andor (200÷1050 nm)
- Symphony InGaAs detector LN-IGA-512x1, Horiba Jobin Yvon (800÷1550 nm)
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Lasers: Ar-Kr laser Stabilite 2018-RM Spectra Physics 2.5W (USA), HeCd laser, Garnet LCM-DTL-374QT
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Ar-Kr laser Stabilite 2018-RM Spectra Physics 2.5W (USA) (454.5 nm, 457.9 nm, 476.5 nm, 488.0 nm, 496.5 nm, 514.5 nm, 520.8 nm, 530.9 nm, 568.2 nm, 647.1 nm)
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HeCd laser (325 nm)
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Garnet LCM-DTL-374QT (355 nm)
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Optical micro-cryostat RC102-CFM (CIA CRYO Industries, USA)
- low vibrations ≤15 nm,
- temperature range Т = 3.5 ÷ 325 К
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Micro-stage, Linkam Scientific Instruments THMS600 (England)
- temperature range Т = 78 ÷ 600 K
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Results
- The possible direction of spontaneous magnetic field in periodically-doped nanostructures has been theoretically established using symmetry analysis.
- Preliminary theoretical investigations of ferrimagnetic structures have been proposed.
- First ZnO nanorods have been grown on substrates covered with Ag layers. Concentration of magnetic atoms along the rods is too low and not uniform. Spinel structures have been put into evidence.
- First GaN sample co-doped with Mn and Mg have been grown and are now under characterization.
- Magnetoconductivity in GaN samples as well as some properties of (Al,Ga)N samples, both doped with Mn, have been investigated.