Effect of Annealing Atmosphere on the Optical and Electrical Properties of Al-Doped ZnO Films and ZnO Nanorods Grown by Solution Process

We demonstrated the synthesis of highly transparent conductive Al-doped zinc oxide (AZO) films through sequential nucleation and growth using a hydrothermal process. Vertically-aligned zinc oxide nanorods (ZnO NRs) were grown on the as-synthesized AZO films and the seed layer formed on glass/AZO by a low-temperature solution process. The ZnO NRs were randomly grown on the as-deposited AZO films. However, a high density of ZnO NRs grew vertically on the seeded AZO films. The influence of annealing atmosphere on the optical and electrical properties of as-deposited AZO films and after growing ZnO NRs on AZO films were performed by annealing in air, hydrogen, oxygen, nitrogen and argon ambient. The results indicated that the resistivity and mobility were lowest for argon-annealed samples, whereas the carrier density was highest. The normalized PL peak intensity of argon-annealed sample in visible region was highest due to increase in surface defects.