Al-doping and Properties of AZO Thin Films Grown at Room Temperature: Sputtering Pressure Effect

• Autor(a) principal: Chaves, Michel [UNESP]
• Data de Publicação: 2019
• Outros Autores: Ramos, Raul [UNESP], Martins, Everson [UNESP], Rangel, Elidiane Cipriano [UNESP], Cruz, Nilson Cristino da [UNESP], Durrant, Steven Frederick [UNESP], Ribeiro Bortoleto, Jose Roberto [UNESP]
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1590/1980-5373-MR-2018-0665; http://hdl.handle.net/11449/186744
• topic: ZnO:Al thin films; TCO; morphological properties; structure zone diagram; room temperature

Aluminum zinc oxide (AZO) thin films were synthesized on glass substrates by radio frequency (rf) magnetron sputtering from a metallic Zn-Al (5 at. %) target at room temperature. The morphological, structural, electrical and optical properties of the films were studied as a function of the sputtering pressure, which was varied from 0.1 to 6.7 Pa. X-ray diffraction (XRD) analyses revealed that the films obtained were polycrystalline, having a hexagonal wurtzite structure with a preferential orientation in the (002) plane. In addition, the crystallite size increased as a function of sputtering pressure. Owing to the re-sputtering of the Zn atoms from the growing film, the aluminum concentration presented a maximum value of 13 at. %. At pressures close to 0.16 Pa, we obtained films with values of electrical resistivity and mobility of 2.8 10(-3) Omega cm and 17 cm(2)/Vs, respectively. Finally, our results indicate that the structure zone diagram proposed by Thornton and later modified by Kluth does not fully predict the structural/morphological behavior of the AZO films, since plasma interactions must also be taken into account. With the methodology used, transparent conductive electrodes can be deposited on substrates at low temperatures.