Strain enhanced electron cooling in a degenerately doped semiconductor

Authors :: Prest, M. J.
Muhonen, J. T.
Prunnila, M.
Gunnarsson, D.
Shah, V. A.
Richardson-Bullock, J. S.
Dobbie, A.
Myronov, M.
Morris, R. J. H.
Whall, T. E.
Parker, E. H. C.
Leadley, D. R.
Source :: Applied Physics Letters 99, 251908 (2011)
Publication Year :: 2011
Abstract: Enhanced electron cooling is demonstrated in a strained-silicon/superconductor tunnel junction refrigerator of volume 40 um^3. The electron temperature is reduced from 300 mK to 174 mK, with the enhancement over an unstrained silicon control (300 mK to 258 mK) being attributed to the smaller electron-phonon coupling in the strained case. Modeling and the resulting predictions of silicon-based cooler performance are presented. Further reductions in the minimum temperature are expected if the junction sub-gap leakage and tunnel resistance can be reduced. However, if only tunnel resistance is reduced, Joule heating is predicted to dominate.<br />Comment: 3 pages, 5 figures