Effects of charging energy on SINIS tunnel junction thermometry

We have investigated theoretically the effects of the charging energy to the normal metal–insulator–superconductor (NIS) tunnel junction used as a thermometer. We demonstrate by numerical calculations how the charging effects modify NIS thermometry, and how the voltage–to–temperature response and the responsivity $\mathrm{\mid }dV\mathrm{/}dT\mathrm{\mid }$ of a current biased thermometer are affected. In addition, we show that the responsivity of the thermometer can be modulated with an additional gate electrode. The maximum responsivity is achieved when the Coulomb blockade is maximal, i.e. with a closed gate.