On-Chip milliKelvin Electronic Refrigerator for Astronomical and Quantum Device Applications

Lead Research Organisation: Royal Holloway, University of London
Department Name: Physics


We intend to develop a new user-friendly technology that would enable small devices to be cooled to exceedingly low temperatures (<100mk). Such a capability will allow diverse and futuristic applications to flourish. These include the detection of black holes, cancer detection and quantum computing. We propose to do this by using an electronic cooling process where relatively energetic (hot) carriers (electrons or holes) quantum mechanically tunnel out of a medium, thereby causing the average electronic temperature in the medium to decrease. The application of this process to realise extremely low temperatures is very new, and we want to greatly improve its efficiency by introducing a new generation semiconductor SiGe into the design of the electronic cooler and, along with it, the well developed silicon processing techniques - so that, ultimately, such coolers can be produced economically and to industrial standards. Coolers will be fabricated around the periphery of a small silicon chip with thermal links to the active device ( payload ) mounted in the centre of the chip. This requires very good thermal design such that the electronic cooler efficiently cools the payload. However, in some cases, it is only necessary to cool the electrons / not the lattice atoms; here SiGe gives a lot of flexibility in controlling the thermal coupling between the electrons and the lattice. Such electronic coolers can operate from a starting temperature of 0.3K, which can be produced by a cryogenic fluid-free closed-cycle helium cryostat, so that a turn-switch technology can be envisaged enabling access to ~10mK working environments. This will be a huge technology step forward, as existing techniques require massive and complex cryogenic fluid-based equipment.During the first phase of the project we will examine several approaches to the realisation of effective electronic cooling, exploiting the wide range of fundamental electronic conditions that can be obtained at very low temperatures in SiGe with its associated metal silicides / thereby enhancing carrier transport and thermoelectric effects. The new coolers will then be tested in two areas of great topical interest, namely radiation detectors and quantum information devices. They could dramatically enhance our ability to detect, for example, the photons that emanate from the earliest black holes, with satellite-based detectors operating at <100mK. And, very significantly, such detectors could revolutionize the fluorescence light detection that is used extensively in biomedical research, enabling advances in our understanding of genetically-based diseases (e.g. cancer) and the workings of a single cell. Furthermore, the computational vista that is opened-up by the quantum computing era requiring qubit devices operating at 10-20mK, is truly awe inspiring. Warwick is co-ordinating the project and has assembled a tightly knit consortium of scientists and engineers with appropriate expertise from four UK universities -Warwick, Cardiff, Leicester and London(Royal Holloway) - and four leading-edge companies, concerned with the development of this technology and the demonstration of its applicability and advantages in two key areas. We are also working closely with Europe's leading centre on mK coolers (Helsinki University of Technology). The UK is exceedingly well positioned to derive benefit from this genuinely new and exciting technology, and this project will sow the seeds for its realisation.


10 25 50
Description A deep understanding of the science and technology of on-chip cooling was obtained. The technology needs further work to be successful. We were successful in operating quantum devices without on-chip cooling.
Exploitation Route There is an opportunity to develop this technology in the UK.
Sectors Aerospace, Defence and Marine,Electronics

Description It has become clearer from this work that the original aim of simpler, smaller refrigeration devices is increasingly necessary to develop. This technology will underpin almost all superconducting quantum technology, making it available at a consumer rather than laboratory level. It may also improve other quantum technologies.
First Year Of Impact 2018
Sector Electronics
Description "in vivo" Modification of Superconducting Quantum Electronic Circuits
Amount £2,206,800 (GBP)
Funding ID EP/R025487/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 04/2018 
End 03/2019
Description EMPIR
Amount € 1,631,544 (EUR)
Funding ID 17FUN10 Parawave 
Organisation European Association of National Metrology Institutes (EURAMET) 
Sector Charity/Non Profit
Country Germany
Start 07/2018 
End 06/2021
Description Quantum technology capital: UK Superconducting Quantum Technologies
Amount £2,711,070 (GBP)
Funding ID EP/N015088/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 04/2016 
End 03/2019
Description Aalto 
Organisation Aalto University
Department Department of Applied Physics
Country Finland 
Sector Academic/University 
PI Contribution Scientific and technical discussions, sample fabrication
Collaborator Contribution Scientific and technical discussions, access to sample fabrication facilities.
Impact unfinished
Start Year 2008