OPTIMIZATION OF CHARGE SENSITIVITY OF A SINGLE-ELECTRON TUNNELING TRANSISTOR WITH A SUPERCONDUCTING GRAIN

Assuming the absence of 1/f noise, we have calculated the charge sensi tivity (CS) of a capacitive-coupled double-junction single electron tu nneling transistor (SETT) with a superconducting grain, operating at l ow temperature and low bias voltage such that the tunneling current is dominated by the Andreev process. In this case the effect of co-tunne ling is suppressed without using the complicated fabrication method. W e have used a realistic sample to demonstrate the procedure of optimiz ing the CS of a SETT with respect to relevant physical parameters and structure parameters. With the presently available fabrication technol ogy, our theoretical analysis can serve as a guide for increasing the CS of a SETT beyond 10(-6) e/root Hz. (C) 1996 American Institute of P hysics.