The effect of the Al distribution on the electrical properties of Al-doped ZnO (AZO) films deposited by atomic layer deposition (ALD) is investigated. In order to control the Al distribution, the pulsing time of trimethylaluminum (TMA) is varied from 2 (within an ALD window) to 0.1 s. As a result, the areal density of Al atoms incorporated in a single dopant layer decreases from 3.3 1014 to 1.2 × 1014 cm-2. Hall measurements reveal that the minimum resistivity of the ALD-AZO films is decreased from 3.2 × 10-3 to 1.7 × 10-3 ωcm as a result of reducing the TMA pulsing time from 2 to 0.1 s. This decrease is due to the obvious increase of the carrier concentration from 1.4 1020 to 4.7 × 1020 cm-3. It is suggested that both the improved doping efficiency (from 13 to 58) and the insertion of more dopant layers within the ZnO matrix are responsible for the increase of the carrier concentration.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films
- Materials Chemistry