| In the past decade, nanomechanical resonators have found use in the work towards understanding mesoscopic quantum systems and the necessary validation of quantum mechanics on this scale. In 2010, the observation and state manipulation of a nanomechanical quantum system was achieved for the first time by O'Connell et al. In 2002, Knobel and Cleland proposed to use a radio frequency superconducting single-electron transistor (RF-SSET), a fast and sensitive charge amplifier, to sense the quantum-limited motion of a piezoelectrically coupled nanomechanical resonator. The work presented in this thesis is towards the realization of the RF-SSET component of this device. An in-house fabrication recipe for making SETs with tunnel junction areas ≤ 1002 nm2 and resistances between 20 kO and 150 kO was developed, in the end producing six SETs with resistances 36 +/- 8 kO that were not susceptible to aging effects. Three measurement circuits were designed and used to characterize one of these SETs in the superconducting state (SSET) and operated in the DC and RF modes in a cryostat at a base temperature of 320 mK. Lock-in measurements revealed the SSET junction capacitances as 206 and 305 aF, contributing to a charging energy of 296 +/- 11 mueV. The resonant LC tank, which permitted RF operation, was also characterized at base temperature. The charge sensitivity of the RF-SSET was 6.8 x 10-5e/ Hz (with uncertainty between 9.6 x 10-4 e/ Hz and 3.5 x 10-5e/ Hz ). With moderate improvements to the impedance matching network formed with the LC tank and greater junction resistances, an RF-SSET charge sensitivity on the order of mue/ Hz , required for sensing the quantum-limited motion of the nanomechanical resonator, should be achieved. |
