Single shot measurement in silicon single electron transistors

A major problem of usual current measurement setup is the severe limitations on the bandwidth due to room temperature electronics. This restricts the practical measurement rate to below 10 Hz and makes impossible to observe the evolution of a quantum state in real time. Here we describe a measurement on a silicon single electron transistor (SET) carried out using a custom CMOS measurement circuit in close proximity to the device under test. Both the device and the CMOS circuit are maintained in the same cryogenic environment. Quantum mechanical states in the single electron transistor (SET) were mapped by continuous microwave spectroscopy. The real time evolution of a particularly long lived quantum mechanical state was observed in a single shot measurement, made possible by the much faster measurement rate. This technique will shortly be applied to the measurement of coherent states in a charge qubit device made of a silicon double dot.