Include Product Page Al2O3_Material Information

Single crystal sapphire Al2O3 is chemically stable, electrically insulating, hard, temperature resistant and has high transparency in the UV-Visible wavelength range. It is easy to make in large crystals and due to its very high hardness it is possible to polish them to an atomically flat surface. As such it is a common choice for the growth of many thin films as well as other uses in and around the lab as a cheap, reliable flat surface. 

Sapphire (α-Al2O3) as a hexagonal structure, belonging to the space group R3c, can be expressed both as a hexagonal (4 indices hkil) or as a rhombohedral unit cell (hkl). The Al atoms are octahedrally coordinated by six oxygen atoms. The oxygen ions nearly form a hexagonal close-packed structure with aluminium ions (Al3+) filling two-thirds of the octahedral interstices. Each Al3+ center is octahedral.

The figure below shows the common planes of Sapphire and those available from Crystal Substrates. C-Plane and A-plane are the most commonly used in the lab, but each have their use for stabilizing growth of specific orientations of thin film materials.

As Al2O3 is highly transparent (>85% in near UV-Visible-IR range 0.17 to 5.5 μm), it is commonly purchased double side polished so that you can perform transmission / absorption spectroscopy on thin films. But for any other use can be purchased single side polished.

There is too much information out there on sapphire substrates and their uses to summarise here fully but if you have any questions, feel free to get in contact at

Commonly grown materials on sapphire substrates: 
ZnO, β-Ga2O3, AlN, GaN, CuGaO2, TiO2, LiCoO2, Spinel battery materials