The NanoSilicon group, in the Warwick physics department, was awarded a major research grant to develop miniature electronic refrigerators that can be fabricated on a silicon chip in 2008. The award is one of only five supported by Research Councils UK this year under their prestigious Basic Technology programme, which aims to turn academic scientific research into technologies that can underpin future research and/or lead to real products.

Instead of using the current complex, slow and bulky liquid helium based technology, this offers the opportunity to cool just the essential operational parts of a system at the flick of a switch. We are calling this silicon based refrigeration technology COOLTRONICS!

Warwick has brought together a consortium of UK universities and spin-out companies together with partners in Finland in a £2.7M project that will last for five years. Each partner brings complimentary expertise to the research, semiconductors at Warwick, thermoelectrics from Cardiff, low temperatures at Royal Holloway and space applications from Leicester. The Finnish groups, from Helsinki, bring a fabrication capability and are currently the world leaders in electronic refrigeration. When it comes to the exploitation stage in a few years’ time, small companies are already lined up with interests in using the technology for improving their own refrigerators, making x-ray detectors to detect anything from the remnants of black holes or early signs of cancer or enabling quantum information processing. Looking further ahead, cooling from room temperature to within a fraction of degree above absolute zero at the press of a button is appearing possible.

Project details

Sponsor	RCUK (EPSRC) EP/F040784/1
Title	On-chip milikelvin electronic refridgerator for astronomical and quantum device applications
Dates	Oct. 2008 to Oct. 2013

Links to collaborators

• Cardiff Engineering, Thermolectrics Group
• Cardiff Physics and Astronomy
• Leicester Space Research Centre
• Royal Holloway, Low Temperature Physics
• Aalto University
• VTT Technology Research Centre

Project Outputs

The following publications have come out of work on this project:

• Juha T. Muhonen, Matthias Meschke and Jukka P. Pekola,
  Micron-scale refrigerators
  Reports on Progress in Physics 75, 046501, (2012)
• M. J. Prest, J.T. Muhonen, M. Prunnila, D. Gunnarsson, V.A. Shah, J S. Richardson-Bullock, A. Dobbie, M. Myronov, R.J.H. Morris, T.E. Whall, E.H.C. Parker and D.R. Leadley.
  Strain Enhanced Electron Cooling in a Degenerately Doped Semiconductor
  Applied Physics Letters 110, 124503 (2011)
  
• J. T. Muhonen, M.J. Prest, M. Prunnila, D. Gunnarsson, V. Shah, A. Dobbie, M. Myronov, R.J.H. Morris, T.E. Whall, E.H.C. Parker and D.R. Leadley
  Strain control of electron-phonon energy loss rate in many-valley semiconductors
  Applied Physics Letters 98, 182103 (2011)
• N. Vercruyssen, R. Barends, T. M. Klapwijk, J. T. Muhonen, M. Meschke, and J. P. Pekola
  Substrate-dependent quasiparticle recombination time in superconducting resonators
  Applied Physics Letters 99, 062509 (2011)
• J. T. Peltonen, J. T. Muhonen, M. Meschke, N. B. Kopnin and J. P. Pekola
  Magnetic-Field-Induced Stabilization of Non-Equilibrium Superconductivity
  Physical Review B 84, 220502(R),(2011) arXiv:1108.1544
  
• V.A. Shah, M. Myronov, A. Dobbie, M.J. Prest, T. E. Whall, E.H.C. Parker, D.R. Leadley
  Flat Single Crystal Membranes for Sensors and Optoelectronic Integrated Circuitry
   (submitted April 2012)
• M.J. Prest, T.E. Whall, E.H.C. Parker and D.R. Leadley,
  Millikelvin Tunnelling Refrigerators
  CRC Handbook of Thermoelectrics, Review Chapter (In press since Nov 2011)
• J. T. Muhonen, A. O. Niskanen, M. Meschke, Yu. A. Pashkin, J. S. Tsai, L. Sainiemi, S. Franssila, and J. P. Pekola.
  Electronic cooling of a submicron-sized metallic beam.
  Applied Physics Letters 94, 073101, (2009).
• Mika A. Sillanpää, Jayanta Sarkar, Jaakko Sulkko, Juha Muhonen,
  and Pertti J. Hakonen.
  Accessing nanomechanical resonators via a fast microwave circuit.
  Applied Physics Letters 95, 011909, (2009)

And these are some of the conference presentations that have been made:

• V.A. Shah, M. Myronov, C. Wongwanitwatana, R.J.H. Morris, M.J. Prest, J. Richardson-Bullock, E.H.C. Parker, T.E. Whall and D.R. Leadley
  Simple fabrication of suspended Germanium structures and their electrical properties from high quality Ge on Si(001) layers
  Pacific Rim Meeting on Electrochemical and Solid State Science (PRiME 2012), Hawaii, Oct 7-12, (2012)
• V.A. Shah, M. Myronov, C. Wongwanitwatana, R.J.H. Morris, M.J. Prest, J. Richardson-Bullock, E.H.C. Parker, T.E. Whall and D.R. Leadley
  Simple fabrication of suspended Germanium structures and their electrical properties from high quality Ge on Si(001) layers
  International SiGe Technology and Device Meeting (ISTDM 2012), Berkeley, June 4-6, (2012)
• M.J. Prest, J.T. Muhonen, M. Prunnila, D. Gunnarsson, V.A. Shah, R.J.H. Morris, A. Dobbie, M. Myronov, T.E. Whall, E.H.C. Parker, D.R. Leadley
  Reduction of Electron-Phonon Conductance in Strained Silicon
  13th International Workshop “Cryogenic Nanosensors” Bjorkliden, Kiruna, Sweden, March 20-27, (2011)
• J. S. Richardson-Bullock, M.J. Prest, J.T. Muhonen, M. Prunnila, D. Gunnarsson, V.A. Shah, R.J.H. Morris, A. Dobbie, M. Myronov, T.E. Whall, E.H.C. Parker, D.R. Leadley
  Improved Cooling Performance in Strained Silicon Tunnel Junctions
  7th International Conference on Si Epitaxy and Heterostructures (ICSI-7), Leuven, Belgium, Sept. (2011)
• V.A. Shah, A. Shchepetov, M. Myronov, M.J. Prest, M. Prunnila, C. Wongwanitwattana, T.E.Whall, E.H.C. Parker, and D.R. Leadley
  The Effects of Tensile and Compressive Strain on Ge Membranes
  7th International Conference on Si Epitaxy and Heterostructures (ICSI-7), Leuven, Belgium, Sept. (2011)
• M.J. Prest, J.T. Muhonen, M. Prunnila, D. Gunnarsson, J S. Richardson-Bullock, V.A. Shah, R.J.H. Morris, A. Dobbie, M. Myronov, T.E. Whall, E.H.C. Parker, and D.R. Leadley
  Strained Silicon for Bolometer Applications
  Low Temperature Detectors (LTD 14), Heidelberg, Aug 1-5, 2011.
• M.J. Prest, J.T. Muhonen, M. Prunnila, D. Gunnarsson, J S. Richardson-Bullock, V.A. Shah, R.J.H. Morris, A. Dobbie, M. Myronov, T.E. Whall, E.H.C. Parker, and D.R. Leadley
  Strain Enhancement of Electron Cooling in Silicon-Superconductor Tunnel Junctions
  Low Temperature Physics (LT26), Beijing, Aug 10-17, 2011.

Design of possible mK cooler – cooling key part of system to below 100mK using just electronic cooling.

The payload to be cooled is a Transition Edge Sensor (TES) that gives unsurpassed ability to detect black holes or early stage cancer!