Include Product Page SrTiO3 Nb 0.7_Material Information
- Nb-SrTiO3 (Niobium Doped Strontium Titanate) Single Crystal Substrate
- Doping concentration 0.05-1 wt%
- Lattice parameter: a = 3.905Å
- Crystal Structure: Perovskite, Cubic
- Commonly used as substrate for: Perovskites e.g. LaAlO3, YBCO, BiFeO3, BaxSr1-xTiO3, SrRuO3, and many complex oxide perovskites including titanates, aluminates, ferrites, zirconates and stannates.
- <0.2 nm rms roughness (measured 5x5 µm AFM scan)
- 5x5 mm to 20x20 mm size and customized
- Single or double side polished
- Chemically Stable, electrically conducting Widely used for growing epitaxial perovskite thin films
- Next day delivery
Nb-doped STO is used to grow films (often perovskites) where a electrical connection is required for the device being created or the testing of the film. We stock Nb-Concentration 0.7 wt% which gives good conductivity without shifting the lattice parameter too much therefore similar films can be grown as with SrTiO3. We can also provide this in 0.05%, 0.1% or 0.5% and 1% if required.
Due to the processing of Nb-STO it is more expensive than STO, so typically people get their growth conditions right on STO before transitioning over to Nb-STO. Or at least the films which do not require electrical connection are grown on STO.
In Nb Doped STO - Nb5+ substitutes Ti4+ in the lattice, bringing more oxide ions or more electrons into the system. In the range of 0.05-1 wt% this dramatically increases the electrical conductivity, the resistivity continues to drop with Nb content from around 0.07 ohm.cm at 0.05 wt% Nb doping to 0.004 ohm.cm at 0.7% Nb. For a full write up on SrTiO3, please refer to the SrTiO3 product page.
An alternative to using Nb-SrTiO3 is depositing a thin layer of highly conducting (metal like) SrRuO3 - this is a lattice matched material with metal like conductivity and even a 20 nm layer can be used as a good electrical connection. It has high conductivity but can lead to difficulties in making the connection to the film if subsequent layers are very thick. SrRuO3 are readily grown by PLD at around 600C -700 C and 150 mTorr. Ruthenium makes the targets expensive to make and it is difficult to make them very dense so they last for afew years at a time. You can buy targets from PLDTargets.com.
