Novel Mid IR single Photon Detectors for Quantum Systems

This project will develop a new commercial single photon avalanche detector (SPAD) platform for the important SWIR,
MWIR and LWIR spectral ranges (1.7 - 12um). Conventional, many photon, photodiodes have been developed to provide
comprehensive coverage of the IR spectrum and in doing so have enabled a multitude of important photonic applications
and industries. As researchers and industry look to apply emerging quantum photonics, it is evident that available detector
technology is limiting the spectral ranges which can be exploited. Visible and IR applications below a wavelength of 1.7um,
are supported by existing Silicon and InP/InGaAs SPAD technologies. However, beyond these wavelengths there are no
SPAD technologies available and hence no single photon detectors that offer their speed of response, high operating
temperature and compact size, which are essential attributes for commercial viability.
The detector to be developed and prototyped in this project employs a novel barrier based structure, proprietary to
Amethyst Research Ltd. In recent years such barrier based structures have delivered leading performance metrics in many
photon IR detectors. The Amethyst barrier technology uniquely allows the barrier detector concept to be extended by
exciting internal avalanche gain, as exploited in SPADs. Preliminary characterisation at Lancaster University has
demonstrated this and shown the potential for the new family of SPAD detectors.
The project has the following milestones
Milestone 1: Design of Single Photon Quantum Avalanche Photo Diode (APD) based on Unipolar Barrier Detector (UBD)
architecture (Amethyst Research and Lancaster University)
Milestone 2: MBE Growth of the Quantum APD Structure (Lancaster University)
Lancaster University have vast experience in growing III-V related semiconductor materials. Hence, for this program, the
APD structure will be grown at Lancaster University.
Milestone 3: Quantum APD Fabrication (CST)
Devices will be processed from wafer grown in Milestone 2 using state-of-the-art cleanroom facilities at Compound
Semiconductor Technologies (CST).
Milestone 4: Quantum APD Testing and Sub-System Integration (Amethyst Research, Lancaster University and
subcontracted system OEMs)

This project targets the development and assessment of an innovative new product with a clear application focus. The
project is motivated by market demand and will be led by the industrial partner under the TSB scheme. This brings a direct
path to realising impact and a supply chain of companies who stand to benefit directly. These are:
Lancaster University - As science providers Lancaster will benefit from the opportunity to apply their scientific
understanding to deliver impact outside the research community and maintain strong industrial partnerships. Through
involvement in the project it will also develop postgraduate and researcher skills in technology development and working
with industry. These will be beneficial to the researchers involved and the wider economy.
Amethyst research Ltd. - As project leaders Amethyst are central to the development of this work into a product and the
realisation of benefit from it. Amethyst will "own" the product to be developed. Through a mixture of in-house and
subcontracted work they will build the value into the product and sell it to end users. A core anticipated impact is hence that
Amethyst will gain new capability and a new successful product, which would support their expansion in the UK and create
new jobs.
Compound semiconductor technologies Ltd. - Form a critical part of the subcontracted fabrication supply chain planned to
produce the new device and fabrication the new product would bring new revenue and support new jobs.
As these companies benefit from new revenue and create new jobs this will bring positive economic impact into their local
communities and the wider economy. Indeed as a high value added product with significant export potential, the single
photon detectors to be developed will bring money into the UK with national benefit.
Beyond these companies, the system integrator will also stand to benefit significantly. The coverage of an expanded IR
spectral range will lead to product differentiating capability. Furthermore a valuable impact of this project would be the skill
development of today's young researchers and engineers, who are required to maintain our high technology industries.
Societal impacts and benefits are also anticipated. Health focused applications of the single photon sensitivity could
improve testing for some of the most significant diseases facing society, including cancer. Early, cost effective and reliable
diagnosis would improve survival rates and reduce treatment costs. Environmental sensing and monitoring applications will
lead to better control and tracking of emissions as well as better understanding of sources and sinks, which would support
long term strategic improvement actions for the benefit of those nationally and internationally.