ON THERMOMETER OPERATION OF ULTRASMALL TUNNEL-JUNCTIONS

The temperature dependence of the I-V characteristics of many single-e lectron tunneling devices enables thermometer operation of these syste ms. Two normal conducting kinds of them are investigated, a) a single junction in a high-impedance environment and b) a double junction. The characteristics of both devices show a cross-over from Coulomb blocka de at low temperatures to ohmic behavior at high temperatures. The rel ated differential conductivity dip allows the determination of the tem perature of the junctions. Both configurations a) and b) are expected to work at least within the range 0.5 less than or equal to beta E(c) less than or equal to 10, where E(c) is the Coulomb energy of the syst em under investigation. An analytical solution for both low- and high- temperature cases of a) and b) as well as numerical results and their fit are presented, including the effect of co-tunneling in case of a d ouble junction.