The crystal is hexagonal and can be grown hydrothermally at a cost that keeps large substrates affordable. Optical transmission in the 0.4 to 0.6 µm range is above 50% at 2 mm thickness, and the material is transparent and conductive enough to serve as a transparent electrode. It is chemically and thermally stable and shows voltage-dependent behaviour that makes it useful in protection devices.
Standard sizes 25×25×0.5, 10×10×0.5, 10×5×0.5 and 5×5×0.5 mm, orientation <0001>, <11-20> or <10-10> at ±0.5°, single or double side polished to Ra ≤ 5 Å over 5×5 µm. Special orientations and sizes are cut to requirement, and an AFM test report can be supplied with the shipment. Packed in a Class 100 clean bag inside a Class 1000 clean room.
Minimum order 10 pcs. Send the orientation, size and thickness; special orientations are quoted from the drawing.
Crystal structure | Hexagonal
Lattice constant | a = 3.252 Å, c = 5.313 Å
Density | 5.7 g/cm3
Growth method | Hydrothermal
Mohs hardness | 4
Melting point | 1975 °C
Band gap | about 3.37 eV
Thermal expansion | 6.5 × 10-6 /K along a, 3.7 × 10-6 /K along c
Heat capacity | 0.125 cal/g
Thermoelectric constant | 1200 mV/K at 300 °C
Thermal conductivity | 0.006 cal/(cm·K)
Transmittance | above 50% at 0.4-0.6 µm, 2 mm thickness
Orientation | <0001>, <11-20>, <10-10> at ±0.5°
Dimension | 25×25×0.5 mm, 10×10×0.5 mm, 10×5×0.5 mm, 5×5×0.5 mm
Customisation | Special orientation and size substrates cut to customer requirement
Surface roughness | Ra ≤ 5 Å over 5×5 µm; AFM test report available
Polishing | Single side or double side
Packing | Class 100 clean bag, Class 1000 clean room
Minimum order | 10 pcs

