LAUSR

Understanding the stability and deposition parameter dependence of intrinsically conductive undoped ZnO prepared by thermal atomic layer deposition is mandatory for future applications. The authors investigate the conductivity of ZnO films deposited at temperatures between 100 and 200 °C as well as its evolution over a period of 160 days under different storing conditions. Most importantly, the conductivity increases by about 1 order of magnitude when the deposition temperature is increased from 100 to 150 °C. Highest conductivities of up to 170 S/cm are reached for ≥175 °C, and these samples do not show any aging effects of the conductivity under ambient storing conditions. In contrast, for deposition temperatures ≤150 °C, accelerated aging led to a significant decrease in conductivity. The best trade-off between the low deposition temperature and good long-term stable conductivity is found to be at 175 °C. A correlation between the intensity of the well-known defect photoluminescence peak (∼1.9 eV) and ...