Investigation of Carrier Transport in GaN Single Crystals and Radiation Detectors by Thermally Stimulated Methods

• Authors: V. Kažukauskas , V. Kalendra , J. Vaitkus
• Languages of publication: EN

Abstracts

EN

We investigated single crystals of GaN and thin film GaN radiation detectors by thermally stimulated currents and thermally stimulated depolarization methods in order to characterize carrier transport properties as influenced by material defect structure. In thick GaN no expressed structure of the thermally stimulated current spectra was observed in the temperature range from 100 K up to 350 K, which could be characteristic of the thermal carrier generation from trap levels. The experimental facts imply that the thermally stimulated current spectra might be caused not by carrier generation, but it could be due to thermal mobility changes. Therefore we had applied the numerical analysis by taking into account carrier scattering by ionized impurities and phonons. It was found that mobility limited by ionized impurities varies as T^{2.8} and lattice scattering causes the dependence T^{-3.5}. The highest mobility values were up to 1550 cm^2/(V s) at 148-153 K. Such high values indicate relatively good quality of the single GaN thick crystals. In high resistivity GaN detectors irradiated by high doses of high-energy neutrons and X-rays current instabilities were observed which could be caused by the change of carrier drift paths in a highly disordered matter. A model of carrier percolation transport is presented.

Keywords

EN

72.20.Jv; 72.20.Fr; 72.80.Ey; 78.70.-g; 85.30.De

Discipline

• 85.30.De: Semiconductor-device characterization, design, and modeling
• 72.80.Ey: III-V and II-VI semiconductors
• 72.20.Fr: Low-field transport and mobility; piezoresistance
• 78.70.-g: Interactions of particles and radiation with matter
• 72.20.Jv: Charge carriers: generation, recombination, lifetime, and trapping

• Journal: Acta Physica Polonica A
• Year: 2005
• Volume: 107
• Issue: 2
• Pages: 340-345

Dates

published

2005-02

received

2004-08-22

Contributors

author

V. Kažukauskas

• Semiconductor Physics Department and Institute of Materials Science and Applied Research, Vilnius University, Saulėtekio al. 9, bldg. 3, 2040 Vilnius, Lithuania

author

V. Kalendra

• Semiconductor Physics Department and Institute of Materials Science and Applied Research, Vilnius University, Saulėtekio al. 9, bldg. 3, 2040 Vilnius, Lithuania

author

J. Vaitkus

• Semiconductor Physics Department and Institute of Materials Science and Applied Research, Vilnius University, Saulėtekio al. 9, bldg. 3, 2040 Vilnius, Lithuania

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Identifiers

DOI

10.12693/APhysPolA.107.340