Ultra‐thin (002)‐oriented Al‐doped zinc oxide transparent electrode grown on oxygen‐controlled homo‐seed layer

Abstract

Highly (002)‐oriented Al‐doped zinc oxide (AZO) thin films with the thickness of less than 200 nm have been deposited on an oxygen‐controlled homo‐seed layer at 200 °C by DC magnetron sputtering. With the homo‐seed layer being employed, the full‐width at half maximum (FWHM) of the (002) diffraction peak for the AZO ultra‐thin films decreased from 0.33° to 0.22°, and, the corresponding average grain size increased from 26.8 nm to 43.0 nm. The XRD rocking curves revealed that the AZO ultra‐thin film grown on the seed layer deposited in atmosphere of O2/Ar of 0.09 exhibited the most excellent structural order. The AZO ultra‐thin film with homo‐seed layer reached a resistivity of 4.2 × 10–4 Ω cm, carrier concentration of 5.2 × 1020 cm–3 and mobility of 28.8 cm2 V–1 s–1. The average transmittance of the AZO ultra‐thin film with homo‐seed layer reached 85.4% in the range of 380–780 nm including the substrate. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Possibilities of Increasing the Usability of Sputtered AZO Films as a Transparent Electrode

“…However, this relationship is not always valid as the reducing of the oxygen result in deterioration of preferential orientation and at the same time to improve electrical properties . The better preferred orientation can be caused by the external substrate heating or deposition on the buffer layer . On the contrary, the impact of high energy particles results in the deterioration of crystallinity and the change of preferential orientation …”

Zn interstitials and O vacancies responsible for n-type ZnO: what do the emission spectra reveal?

“…Its wide direct band gap (3.4 eV) and high exciton binding energy has made ZnO 1 a promising candidate for varied optoelectronic applications, 2,3 primary among which is its utility as a transparent but conducting medium. 4,5 While most forms of undoped ZnO, at room temperature (RT), show n-type character, p-type ZnO is rarely prepared, intentionally or otherwise. 1,6 The debate as to the origin of this n-type character and the associated donor states has mostly centred around two doubly occupied contenders; the oxygen vacancy (V O ) states and interstitial Zn (I Zn ) related defect states.…”

Flexible transparent conductive films on PET substrates with an AZO/AgNW/AZO sandwich structure

“…In addition, the brittle nature of ITO lms limits its application in exible electronics because the lms crack easily when the substrate is bent. To solve these problems, various indium-free materials, including other oxide lms, 5,6 metal thin lms, 7 metal nanowires, 8,9 graphene 10 and carbon nanotubes, 11 have been investigated as compelling alternatives to ITO. Among these alternatives, AgNW lms have been attracting greater interest because of their intriguing electrical, optical and mechanical properties.…”