Nanostructured Aluminium Doped Zinc Oxide (AZO) Sputter Targets – Properties and Applications

By AZoNano

Table of Contents

Overview
Properties of Aluminium Doped Zinc Oxide Targets
Properties of AZO Sputtered Films
Applications
     Photovoltaic Applications
About INNOVNANO

Overview

AZO is a high purity nanostructured aluminium doped zinc oxide with typical aluminium content between 0.5 to 2 wt%. Innovnano also offers custom combinations. The Aluminium doping causes the material to develop distinct properties that ensure that the product is suitable for transparent conductive thin films for use in this film photovoltaic applications such as CIGS, Cd-Te, amorphous silicon-Si and microcrystalline solar cells.

Innovnano processes the high purity AZO powder into dense sputter coating targets for photovoltaic manufacturers to use in the manufacture of transparent conductive oxide layers. Their process produces nano-sized powders that sinter at lower temperatures, enabling them to maintain their small grain size and uniform distribution of aluminium in the zinc oxide matrix.

Properties of Aluminium Doped Zinc Oxide Targets

The properties of aluminum doped zinc oxide sputter targets for photovoltaics and glass are shown in the table below:

Physical Properties
Sputter mode RF, DC
Density (g/cm3) >99.8
Composition 0.5 - 2.0 wt%
Electrical Resistivity (bulk) < 5 x 10-3 ohm.cm
Average Grain Size < 5 μm
Appearance
Dark green

Innovnano AZO sputter targets exhibit a homogenous grain structure which leads to consistent and high quality sputtering performance.

Figure 1. Typical SEM image of the surface of Innovnano AZO sintered target.

Properties of AZO Sputtered Films

AZO thin films are electrically conductive and exhibit high levels of transmittance in the visible region and usable transmission to IR wavelengths up to 12μm. AZO offers an viable alternative to other materials such as indium tin oxide (ITO) for reasons such as:

  • Lower cost
  • Increased abundance
  • High thermal stability
  • Non-toxicity

Figure 2. SEM image of sputtered AZO film on glass.

Figure 3. Transmittance of an AZO thin film on glass.

Applications

AZO thin films have the potential to be used in:

  • Solar cells
  • LCD electrodes
  • Touchscreen transparent contacts
  • Flat panel displays
  • IR windows

Photovoltaic Applications

In CIGS and Cd-Te solar cells, the AZO materials are deposited in the module stack as a transparent front contact on top of the absorber and intermediate layers. In contrast, the AZO is used to deposit reflective layers on the substrate or transparent conducting oxide in the top layer in amorphous silicon-Si and microcrystalline photovoltaics.

When used in the top layer important properties of the AZO layer include:

  • High transparency in the VIS/near IR spectrum
  • A surface texture that promotes light scattering and absorption within the cell
  • Excellent chemical stability
  • Excellent bonding to silicon

About INNOVNANO

INNOVNANO (part of CUF, the largest Portuguese chemical group), with its corporate Headquarter located in Lisbon, has developed a unique and innovative proprietary patented process. The process is defined as high-pressure semi continuous process for the large-scale production of nanomaterials and advanced ceramic powders.

Using this technology INNOVNANO is able to produce commercial quantities of metal oxides, doped metal oxides, and composite nanoparticles in the range of 20 nm to 60 nm.

This information has been sourced, reviewed and adapted from materials provided by INNOVNANO.

For more information on this source, please visit INNOVNANO.

Date Added: Feb 10, 2012 | Updated: Jun 11, 2013
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