Novel imaging and sensing systems earn £300 million in UK exports
Our research underpins the UK industry’s global position in high performance millimetre-wave and terahertz imaging and sensing devices. Commercial sales driven by this research – from clinical terahertz imaging systems to car radars for automated cruise control – have totalled more than £300 million to date.
Technologies which emit and detect electromagnetic radiation – from the humble household CD player to advanced terahertz cameras – are essential components in a range of industrial, medical and consumer electronics applications. The quality and capabilities of these devices continues to improve as manufacturing methods and signal processing techniques combine to boost sensitivity, temperature stability and signal-to-noise ratios.
Researchers in the School have developed several fabrication techniques that improve the performance of the wafers used for millimetre-wave and terahertz generation and detection.
In a large applied project, the researchers worked with several companies – e2v, Teraview, Renishaw, , and the defence technology firm Selex Galileo – and developed high-speed devices, magnetic sensors, broadband terahertz sources and terahertz detectors. The devices now all enjoy commercial success.
In particular the research team designed for e2v novel epitaxial wafers which had better temperature stability and greater efficiency compared to existing industrial counterparts. Since 2008 e2v has sold over 100 novel wafers each containing up to 10,000 devices for car radars. These have been integrated into Bosch cruise control systems within BMW and Audi cars.
e2v has also manufactured over 500,000 Gunn diode devices for Bosch, worth £6 million in sales for e2v. The Gunn diodes are found in Bosch’s adaptive cruise control systems that are fitted on high end Audi and BMW cars. This optional cruise control system has been installed in 430,000 vehicles.
Devices for detecting radiation now boast better sensitivity, temperature stability and signal-to-noise ratios.
The researchers also perfected methods to produce epitaxial layers – thin layers of crystals whose conductivity can be manipulated. The layers grown in Manchester have an unprecedented lifespan and improve signal-to-noise ratios. Over 30 wafers with these layers have been supplied to Teraview which has used them in their pulsed imaging and terahertz spectroscopy systems. Selling at between £150,000 and £200,000 apiece, the latest model has been sold to laboratories in Europe, North America and the Far East, generating income in excess of £6 million.
In 2008 University spin-out, Advanced Hall Sensors (AHS) was established. This company produces ultra-high precision 2-dimensional electron hag Hall effect sensors. These components, which also integrate semiconductor components fabricated using molecular beam epitaxy, have the highest sensitivity of any Hall sensor in the market today. AHS has so far sold over three million sensors to Renishaw PLC which uses them in its £300 million business division making high performance linear encoders for industrial, photovoltaic and consumer electronics.
The main aim of the Molecular Beam Epitaxy research has been to develop high-yielding, high-performance semiconductor components for cost-sensitive markets such as the automotive sector.
The research team supported a major improvement in the performance of detectors by using a technique called molecular beam epitaxy (MBE) for wafer fabrication. Studies showed that MBE could optimise the growth and anneal temperature stages of wafers; MBE allowed the wafers to be precisely tailored to function as terahertz emitters or detectors.
The research also demonstrated how MBE permitted the growth of advanced graded-gap Gunn diodes with graded-gap hot electron launchers. Gunn diodes are used in electronic devices with high frequencies.