Structural, optical and electrical properties of ZnO:Al thin films for optoelectronic applications

Abstract

Undoped and aluminum-doped ZnO thin films are prepared by the sol-gel spincoating process. Zinc acetate dihydrate, ethanol and mono-ethanolamine are used as precursor, solvent and stabilizer, respectively. The atomic percentage of dopant in solution were [Al/Zn] = 1 %, 2 % and 3 %. The effect of Al doping on the optical and electrical properties of ZnO films was investigated by X-ray diffraction (XRD), Four-Point probe technique and UV-visible spectrophotometery. The results from the X-ray diffraction show that the pure ZnO thin films had a polycrystalline structure of the hexagonal Wurtzite Type. A minimum resistivity of 3.3 × 10 −3 · cm was obtained for the film doped with 2 mol % Al. Optical transmissions reveal a good transmittance within the visible wavelength spectrum region for all of the films. The value of the band gap is enhanced from 3.21 eV (undoped ZnO) to 3.273 eV (Al/Zn = 3 %), the increase in the band gap can be explained by the Burstein-Moss effect.

Morphological and electrical evolution of ZnO: Al thin filmsdeposited by RF magnetron sputtering onto glass substrates

“…ZnO:Al and ZnO:Ga thin films have been produced by a wide variety of techniques, including chemical and physical processes, such as pulsed laser deposition 6 , chemical vapor deposition 7 , spray pyrolysis 8 , sol-gel technique 9 , atomic layer deposition 10 and magnetron sputtering 11 onto a variety of substrates. Among these methods, magnetron sputtering is especially interesting, because it can not only be conducted at low temperatures, but can also produce high-quality crystalline intrinsic and doped ZnO thin films 12 .…”

Influence of Sn Low Doping on the Morphological, Structural and Optical Properties of ZnO Films Deposited by Sol Gel Dip-Coating

“…Zinc Oxide (ZnO) thin film has been extensively studied for their attractive properties in electronic and optoelectronic applications [1] such as rectifiers, filters, resonators for radio communications and image processing [2]- [4]. Thin films of Zinc Oxide can also be used in chemical sensors which are highly sensitive gas detectors [5] [6].…”

Porous Zinc Oxide Thin Films: Synthesis Approaches and Applications

“…In this case, doping can be achieved by simply including an additional doping precursor within the synthesis solution, such as aluminum chloride, tin chloride and silver nitrate. This approach was explored to successfully dope porous ZnO with various elements, including Al [67,68], Sn [69], Ag [70], Na [71], Mg [72] and many others [73,74]. Similarly to pristine ZnO, the resulting doped structures were found to be highly promising in view of gas sensors fabrication, especially for ammonia and H 2 S detection.…”