Sapphire substrates are ideal for use instead of glass substrates when optical transmission is required in the ultraviolet (above 200 nm) or infrared (below 5 μm) range. Low-temperature optical measurements will also benefit from the higher thermal conductivity of sapphire substrates, and they may also be used in high temperature environments up to 2300 K.
Product Specifications
We offer sapphire substrates with two different surface finish qualities. Our 'Standard' sapphire substrates have been polished to a surface quality of 60/40 scratch-dig, have an RMS roughness of ~0.3 nm, and are suitable for most applications (including spectroscopy or thin-film deposition).
In comparison, our 'Ultra Smooth' sapphire substrates have been polished to a surface quality of 10/5 scratch-dig, have an RMS roughness of ~0.1 nm, and are suitable for applications involving atomic force microscopy, 2D materals, or any application where surface quality is crucial.
Properties | Standard | Ultra Smooth |
| Substrate size | 20 mm x 15 mm | 20 mm x 15 mm |
| Thickness | 1.1 mm | 1.1 mm |
| Material | Synthetic sapphire | Synthetic sapphire |
| Surface finish (scratch-dig) | 60/40 (both sides polished) | 10/5 (both sides polished) |
| Surface roughness (RMS) | ~0.3 nm | ~0.1 nm |
| Surface orientation | C-plane | C-plane |
| Applications | UV/optical/NIR spectroscopy | Atomic force microscopy, 2D material substrate |
Comparison Between Float Glass and Sapphire
Properties | Float Glass | Sapphire |
Hardness (Mohs) | 5.5 | 9 |
Density (g/cm3) | ~2.5 | 3.975 |
Compressive strength (MPa) | 1000 | 2000 |
Transmission window (nm) | ~350-2000 | ~200-5000 |
Refractive index n (k) 300 nm 600 nm 2000 nm 5000 nm |
1.55 (5.0×10-5) 1.52 (4.5×10-7) 1.50 (4.4×10-6) 1.39 (3.0×10-3) |
1.91 (1.7×10-8) 1.76 (2.0×10-8) 1.74 (2.5×10-8) 1.62 (3.1×10-8) |
Thermal conductivity (W/m.K) 30 K 300 K |
0.2 0.9 |
10000 40 |
Melting point (K) | 950 | 2300 |
Specific heat capacity (J/K.kg) | 870 | 750 |
Chemical Properties
Sapphire is a crystalline form of aluminium oxide (Al2O3). It is formed of Al3+ cations and O2- anions arranged in a hexagonal lattice. It is extremely unreactive and chemically-resistant to acids and alkalis, including hydrofluoric acid.
Mechanical Properties
Sapphire is exceptionally hard with a Mohs hardness of 9, second only to diamond (which has a hardness of 10). For comparison, glass has a hardness of ~5.5. This makes it extremely scratch-resistant.
Optical Properties
Sapphire is birefringent, meaning that its refractive index depends on the direction at which the light propagates through the crystal and its polarisation. While birefringence has uses in various optical elements, it is generally undesirable in a substrate used for optical measurements.
To overcome this, our sapphire is cut along the C-plane which eliminates polarisation-dependent birefringence for normally-incident light. Sapphire is transparent to wavelengths of light between 200 nm and 5 µm, making it an excellent choice for UV and near/mid-IR applications. Sapphire has a refractive index of ~1.76 in the visible spectrum.
Below is a comparison of the optical transmission between our sapphire substrates and our quartz-coated glass substrates, showing the superior UV transmission of sapphire. Note: The lower transmission of sapphire in the wavelength range from 350nm - 1000nm is due to its higher real refractive index (n) causing greater reflection of incident light at the air-substrate interface.
Thermal Properties
Sapphire has a high thermal conductivity of ~40 W/m.K at room temperature. This is almost 50 times higher than glass, and twice as high as stainless steel. This value increases to ~10000 W/m.K as temperature is reduced. This makes sapphire highly suitable for low-temperature optical measurements where thermal equilibrium between the sample and cryostat is required. It is also suitable for use in high-temperature environments up to 2300 K. Our sapphire substrates are polished to optical quality, and have an RMS roughness significantly below than that of our glass substrates.
To the best of our knowledge the technical information provided here is accurate. However, Ossila assume no liability for the accuracy of this information. The values provided here are typical at the time of manufacture and may vary over time and from batch to batch.
About Ossila Founded in 2009 by organic electronics research scientists, Ossila aims to provide the components, equipment, and materials to enable intelligent and efficient scientific research and discovery. Over a decade on, we're proud to supply our products to over 1000 different institutions in over 80 countries globally. With decades of academic and industrial experience in developing organic and thin-film LEDs, photovoltaics, and FETs, we know how long it takes to establish a reliable and efficient device fabrication and testing process. As such, we have developed coherent packages of products and services - enabling researchers to jump-start their organic electronics development program. The Ossila Guarantee Free Worldwide Shipping Eligible orders ship free to anywhere in the world Fast Secure Dispatch Rapid dispatch on in-stock items via secure tracked courier services Quality Assured Backed up by our free two year warranty on all equipment Clear Upfront Pricing Clear pricing in over 30 currencies with no hidden costs Large Order Discounts Save 8% on orders over $10,300.00 and 10% on orders over $12,900.00 Expert Support Our in-house scientists and engineers are always ready to help Trusted Worldwide Great products and service. Have already recommended to many people. Dr. Gregory Welch, University of Calgary Wonderful company with reasonably priced products and so customer-friendly! Shahriar Anwar, Arizona State University The Ossila Team Prof. David Lidzey - Chairman As professor of physics at the University of Sheffield, Prof. David Lidzey heads the university’s Electronic and Photonic Molecular Materials research group (EPMM). During his career, David has worked in both academic and technical environments, with his main areas of research including hybrid organic-inorganic semiconductor materials and devices, organic photonic devices and structures and solution processed photovoltaic devices. Throughout his academic career, he has authored over 220 peer-reviewed papers. Dr. James Kingsley - Managing Director James is a co-founder and managing director of Ossila. With a PhD in quantum mechanics/nanotech and over 12 years’ experience in organic electronics, his work on the fabrication throughput of organic photovoltaics led to the formation of Ossila and the establishment of a strong guiding ethos: to speed up the pace of scientific discovery. James is particularly interested in developing innovative equipment and improving the accessibility of new materials for solution-processable photovoltaics and hybrid organic-inorganic devices. Dr. Alastair Buckley - Technical Director Alastair is a lecturer of Physics at the University of Sheffield, specialising in organic electronics and photonics. He is also a member of the EPMM research group with a focus on understanding and applying the intrinsic advantages of functional organic materials to a range of optoelectronic devices. Alastair’s experience has not been gained solely in academia; he previously led the R&D team at MicroEmissive Displays and therefore has extensive technical experience in OLED displays. He is also the editor and contributor of "Organic Light-Emitting Diodes" by Elsevier. Our Research Scientists Our research scientists and product developers have significant experience in the synthesis and processing of materials and the fabrication and testing of devices. The vision behind Ossila is to share this experience with academic and industrial researchers alike, and to make their research more efficient. By providing products and services that take the hard work out of the device fabrication process, and the equipment to enable accurate, rapid testing, we can free scientists to focus on what they do best - science. Customer Care Team The customer care team is responsible for the customer journey at Ossila. From creating and providing quotes, through to procurement and inventory management, the customer care team is devoted to providing first class customer service. The general day to day responsibilities of a customer care team member involves processing customers orders and price queries, answering customer enquiries, arranging the shipment of parcels and notifying customers of updates on their orders. Collaborations and Partnerships Please contact the customer care team for all enquires, including technical questions about Ossila products or for advice on fabrication and measurement processes. Location and Facilities Ossila is based at the Solpro Business Park in Attercliffe, Sheffield. We operate a purpose-built synthetic chemistry and device testing laboratory on site, where all of our high-purity, batch-specific polymers and other formulations are made. This is complemented by a dedicated suite of thin-film and organic electronics testing and analysis tools within the device fabrication cluster housed in a class 1000 cleanroom in the EPSRC National Epitaxy Facility in Sheffield. All our electronic equipment is manufactured on-site.
