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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Hartnett, John G.
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (7/7 displayed)
- 2011Microwave properties of semi-insulating silicon carbide between 10 and 40 GHz and at cryogenic temperaturescitations
- 2010Detrapping and retrapping of free carriers in nominally pure single crystal GaP, GaAs, and 4H–SiC semiconductors under light illumination at cryogenic temperaturescitations
- 2009Measurements of the complex permittivity and the complex permeability of low and medium loss isotropic and uniaxially anisotropic metamaterials at microwave frequenciescitations
- 2008Modified permittivity observed in bulk gallium arsenide and gallium phosphide samples at 50 K using the whispering gallery mode methodcitations
- 2004The microwave Characterization of Single Crystal Lithium and Calcium Fluoride at Cryogenic Temperaturescitations
- 2004The dependence of the permittivity of sapphire on thermal deformation at cryogenic temperaturescitations
- 2003Lithium tantalate - a high permittivity dielectric material for microwave communication systemscitations
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article
Detrapping and retrapping of free carriers in nominally pure single crystal GaP, GaAs, and 4H–SiC semiconductors under light illumination at cryogenic temperatures
Abstract
We report on extremely sensitive measurements of changes in the microwave properties of high purity nonintentionally-doped single-crystal semiconductor samples of gallium phosphide, gallium arsenide, and 4H–silicon carbide when illuminated with light of different wavelengths at cryogenic temperatures. Whispering gallery modes were excited in the semiconductors while they were cooled on the coldfinger of a single-stage cryocooler and their frequencies and Q-factors measured under light and dark conditions. With these materials, the whispering gallery mode technique is able to resolve changes of a few parts per million in the permittivity and the microwave losses as compared with those measured in darkness. A phenomenological model is proposed to explain the observed changes, which result not from direct valence to conduction band transitions but from detrapping and retrapping of carriers from impurity/defect sites with ionization energies that lay in the semiconductor band gap. Detrapping and retrapping relaxation times have been evaluated from comparison with measured data.