Abstract
We report on measurements of the frequency-dependent conductivity in lithium-diffused (Li-diffused) and annealed GaAs in the frequency range 10-106 Hz and the temperature range 30-300 K. Li diffusion into GaAs reduces the free carrier concentration and can make the material semi-insulating. Using admittance spectroscopy we show that the conduction in semi-insulating Li-diffused GaAs is due to hopping between localized centers. These centers are suggested to be associated with the gallium vacancy V Ga and the gallium antisite GaAs. Furthermore, percolation is apparent in as-diffused samples, indicating that the material contains metallic precipitates. We suggest that the percolation is due to Li precipitation or formation of GaLi clusters during in-diffusion of lithium. At high frequency the AC conductivity is proportional to ωs. The value of s decreases with increasing temperature which suggests a correlated barrier hopping mechanism.
| Original language | English |
|---|---|
| Pages (from-to) | 324-328 |
| Number of pages | 5 |
| Journal | Physica B: Condensed Matter |
| Volume | 340-342 |
| DOIs | |
| Publication status | Published - 31 Dec 2003 |
| Event | Proceedings of the 22nd International Conference on Defects in (ICDS-22) - Aarhus, Denmark Duration: 28 Jul 2003 → 1 Aug 2003 |
Bibliographical note
Funding Information:This work was partially supported by Icelandic Council of Science and the University Research Fund.
Other keywords
- AC conductivity
- Conductivity measurements
- GaAs
- Hopping conduction
- Lithium