| Autor: |
Polyakov, A., Smirnov, N., Govorkov, A., Belogorokhov, I., Scherbatchev, K., Bublik, V., Avdeev, O., Chemekova, T., Mokhov, E., Nagalyuk, S., Helava, H., Makarov, Yu. |
| Předmět: |
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| Zdroj: |
Russian Microelectronics; Dec2011, Vol. 40 Issue 8, p629-633, 5p |
| Abstrakt: |
The structural characteristics and electrical properties of bulk aluminum nitride crystals grown by sublimation and used as substrates for light emitting diode (LED) structures and AlGaN/GaN field effect transistors were studied. The crystalline perfection was assessed by selective chemical etching and by X-ray diffraction techniques. Electrical and optical properties were investigated using the temperature dependence of conductivity, admittance spectroscopy, high-temperature/low-frequency capacitance voltage measurements and by photoinduced transient current spectroscopy (PICTS), microcathodoluminescence (MCL) spectra and MCL imaging techniques. It was established that the studied samples were single crystals with a large grain substructure, with characteristic grain size of several hundred microns and a dislocation density of 10-10 cm inside the grains. The electrical characteristics of the crystals were governed by the compensation of residual donors with a level near E-0.3 eV by deep centers with activation energy of 0.7 eV, both centers manifesting themselves in the temperature dependence of conductivity and in admittance spectra. In addition, deep centers responsible for the luminescence band with the peak energy of 3.3 eV and associated with low-angle grain boundaries were also observed. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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