Comparative investigation of fracture behaviour of aluminium-doped ZnO films on a flexible substrate

Abstract

The differences in the fracture behaviour of aluminium-doped ZnO (AZO) films on a flexible substrate subjected to tensile and compressive strains were investigated by using a simple-support bending method. It is found that the crack density and the crack spacing of the AZO films become saturated both in the face-out (FO) and in the face-in (FI) bending tests when the applied strain reaches a certain value. The saturated crack density of the AZO film in the FO bending is higher than that of the film in the FI bending. Crack-initiation strain of the film in the FO bending is smaller than that of the film in the FI bending. The fracture energy of the AZO films is also analyszed. Failure behaviours of the films are examined and exhibit different failure mechanisms for the films subjected to tensile and compressive strains.

Piezoresistivity of thin film semiconductors with application to thin film silicon solar cells

“…Both curves show a hysteresis. This behavior has most likely nothing to do with a changing band structure but more with cracks that appear perpendicular to the applied strain as observed for both ITO [17,49] and ZnO [18,21,50]. Piezoelectricity of ZnO:Al should not be an important effect because it needs an inhomogeneous strain field which is not the case for our experiments [21].…”

Optical and Electrical Properties of Oxide Multilayers

“…As a result, aluminum-zinc-oxide (AZO) and gallium-zinc-oxide (GZO) materials could become good alternatives to ITO because they have a low resistivity in the order of 10-4 Ω·cm despite being indium-free materials [5,6]. However, these materials still cannot be applied in large area, flexible substrates due to their polycrystalline structure [7,8].…”

Mechanical properties of amorphous indium–gallium–zinc oxide thin films on compliant substrates for flexible optoelectronic devices

“…Chen et al [11] reported buckling experiments carried out on ITO, reporting that the crack onset strain (COS) of the film under tension at 1.1% was less than its value under compression. In addition, Ni et al [12] investigated the fracture properties of AZO-coated on PET substrates under simple-support bending conditions. It was reported that the coating damage, under tensile strain, is caused by the creation of channel cracks, while under compression the film specimen may first delaminate from the polymer substrate and then buckle before the initiation of a crack.…”