Estimation of the charged defect density from hot-electron transport studies in epitaxial ZnO
| Autor: | E. Šermukšnis, A. Šimukovič, Oleg Kiprijanovič, Linas Ardaravičius, M. Ramonas, Arvydas Matulionis |
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| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | Lithuanian Journal of Physics. 60 |
| ISSN: | 2424-3647 1648-8504 |
| DOI: | 10.3952/physics.v60i1.4163 |
| Popis: | High-field electron transport measurements by applying short (few ns) voltage pulses on nominally undoped n-type Zn-polar ZnO epilayers are reported and interpreted in terms of the Boltzmann kinetic equation. The transient measurements do not demonstrate a significant change in the electron density up to 320 kV/cm electric field. This result together with the experimental data on the current allows one to estimate the electron drift velocity from the measured current: the highest value of ~2.9 × 107 cm/s is obtained at the pre-breakdown field of 320 kV/cm for the ZnO layer with the electron density of 1.5 × 1017 cm–3. The densities of double-charged oxygen vacancies (~1.6 × 1017 cm–3) and other charged centres (~1.7 × 1017 cm–3) are assumed for the best fit of the simulated and measured hot-electron effect. A correlation with the epilayer growth conditions is demonstrated: the higher Zn cell temperature favours the formation of a higher density of the oxygen vacancies (1.9 × 1017 cm–3 at 347°C). |
| Databáze: | OpenAIRE |
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