Strontium Titanate SrTiO3 (STO) Crystal Substrates (5pack)

We offer all common sizes of STO up to 30mm (~1.2") diameter. Please contact us here if you would like a quotation for another size. 

Strontium Titanate (STO) SrTiO₃ Single Crystal Substrates

• Commonly used as substrate for: Perovskites e.g. LaAlO₃, YBCO, BiFeO₃, BaxSr1-xTiO₃, SrTiO₃, and many complex oxide perovskites including titanates, aluminates, ferrites, zirconates and stannates.
• <0.2 nm rms roughness (measured 5x5 µm AFM scan)
• Chemically Stable, electrically insulating unless doped with Nb or Fe, stable at high temperature
• Most common substrates used in growing oxide thin films
• Widely used for growing epitaxial perovskite thin films

Strontium Titanate (STO) SrTiO₃ Lattice Match 

Strontium Titanate or SrTiO₃ (STO) single crystal provides a good lattice match to most materials with Perovskite structure and is also used to grow many cubic materials too. Its lattice constant (3.905Å) and a twin-less crystal structure and very good physical and mechanical properties for film growth. 

Strontium Titanate (STO) SrTiO₃ Crystal Structure 

A perovskite is a material that has the same crystal structure as the first-discovered mineral with perovskite crystal structure, calcium titanium oxide. Generally, perovskite compounds have a chemical formula ABX3, where ‘A’ and ‘B’ represent cations and X is an anion that bonds to both. In SrTiO3, Sr sits on the A site, Ti on the B site and as is expected in oxides and thin films, X site is oxygen. However, many perovskite thin films with different A and B cations can be stabilised on SrTiO₃. This opens up STO being used to being the most commonly used substrates to grow and study complex oxide perovskites including but not limited to titanates, aluminates, ferrites, zirconates and stannates.

It is particularly well known as the substrate for the growth of the LSAT interface and being the substrate of choice for epitaxial growth of high-temperature superconductors (e.g. YBCO).

Strontium Titanate (STO) SrTiO₃ Dielectric Constant

SrTiO₃ has an indirect band gap of 3.25 eV and a direct gap of 3.75 eV in the typical range of semiconductors. Synthetic strontium titanate has a very large dielectric constant (300) at room temperature and low electric field. It has a specific resistivity of over 109 Ω-cm for very pure crystals.

Strontium Titanate (STO) SrTiO₃ Melting Temperature

SrTiO₃ material has a melting point of 2080 °C (3776 °F) and is readily attacked by hydrofluoric acid. Under extremely low oxygen partial pressure, strontium titanate decomposes via incongruent sublimation of strontium well below the melting temperature.

Strontium Titanate (STO) SrTiO₃ Lattice Parameter

Its bulk lattice parameter of 3.905Å makes it suitable as the substrate for some noteworthy materials including the growth of LaAlO₃, Barium strontium titanate (BaxSr1-xTiO3, BST), highly conducting strontium ruthenate (SrRuO₃) and many others. 

Strontium Ruthenate SrRuO₃

Strontium ruthenate, SrRuO₃, thin films grown on STO are epitaxial and are highly conducting (almost metallic like conductivity) therefore are commonly grown (15-200 nm thickness) to create a conducting electrode under subsequent layers. 

Strontium Titanate SrTiO₃ Niobium-doped STO

Another option for having a conducting electrode is to start with Niobium-doped STO. Doping strontium titanate with niobium makes it electrically conductive, being one of the only conductive commercially available single crystal substrates for the growth of perovskite oxides. Typical doping concentration of Nb-STO is 0.2-1 at% Nb, with the most commonly used being 0.7at% Nb. Nb-STO is also available from Crystal Substrates here. 

Strontium Titanate (STO) SrTiO3 Custom Sizes 

We can cut SrTiO₃ substrates to your desired dimensions. Please contact us if you require specific dimensions. You can also cut down in the lab with a diamond scribe if required.

If you have any questions please contact us here. 

Dr Joseph Franklin