Single-electron charging effects in one-dimensional arrays of ultrasmall tunnel junctions

Coulomb blockade of single-electron tunneling and high sensitivity to an external electric field has been observed for 1D series arrays of ultra-small-area (<0.1×{}0.1 {μ}m²) tunnel junctions, made of Al/Alₓ{O}y$/Al, at helium temperatures. In particular, the dc voltage V across the array responds strongly to a voltage ${U}g$ applied to a control electrode. For an array of thirteen junctions, the voltage gain ${K}V=δV/δ{U}gof the resulting sub-single-electron- transistors reached 0.2, while the charge sensitivity of the device was as high as 2×{10}^{{{-}}4}$e/${Hz}1/2$ at a frequency f=10 Hz.