Nanocolumnar growth of sputtered ZnO thin films

Sequential sputtering technology was developed for the formation of transparent and conductive very thin films of ZnO doped by Al (AZO) with a nanocolumnar polycrystalline structure. The characterization of their properties, including structural (scanning electron microscopy, X-ray diffractometry), electrical (Hall measurements) and optical (visible spectrometry, ellipsometry), was performed. AZO thin films with thicknesses of approximately 100 nm were prepared with a pronounced nanocolumnar and (002) textured crystalline structure, sufficient low resistivity (≈ 10− 1 Ω cm), satisfactory optical transparency (≈ 90%) and adequate refractive index (≈ 2.0) for future applications in biochemical sensors.