Cadmium telluride (CdTe) family of materials (CdZnTe, CdMnTe etc) is widely recognised as the premier choice of material for digital and spectral radiation detectors. However, it has historically proved very difficult to produce them in a consistent and commercially viable way.

This has meant device and system builders have been unable to design and construct mainstream equipment around CdTe/CZT, although the materials are used in certain high end or cost insensitive applications.

Kromek produces the crystals using a novel vapour phase growth technique (current manufacturers all use techniques based on liquid phase growth) developed over a period of 20 years by the University of Durham. This patented technique is capable of producing material of improved structural integrity, uniform composition and exceptional purity.

There is also improved control of production quality, thus providing high and predictable yields.

The fact the material is grown at low temperature, free from any container walls, and vapour transport conditions are carefully controlled, it results in the following benefits:

• High yield
• Large area wafers
• Inherently lowproduction costs
• Reproducible properties.

Kromek has also developed and uses technology for producing bulk CdTe/CZT crystals on gallium arsenide or germanium substrates. This enables Kromek to produce single crystals wafers which are large and provides a number of important product differentiations in the defense and medical markets. It is worth noting the production of bulk single crystals of CdTe/CZT on gallium arsenide or germanium is a truly groundbreaking step and a world first.

This has enabled Kromek to develop a range of pixilated and planar detectors of various sizes for a variety of applications.