  We have incorporated an aluminum single electron transistor (SET) directly on
top of a vertical quantum dot, enabling the use of the SET as an electrometer
that is extremely responsive to the motion of charge into and out of the dot.
Charge induced on the SET central island from single electron additions to the
dot modulates the SET output, and we describe two methods for demodulation that
permit quantitative extraction of the quantum dot capacitance signal. The two
methods produce closely similar results for the determined single electron
capacitance peaks.
