Fabrication and Measurement of Linear Arrays

This thesis describes the first realization and initial measurements of a linear array of seven quantum dots. The device was fabricated on a high mobility GaAs/AlGaAs heterostructure. Electron beam lithography was used to pattern critical features of the device, and 70 nm resolution was achieved. A 3He probe was used to measure the device at 300 mK. The design of the device allowed individual control over each Quantum Point Contact that defines the dots. It also allowed creating systems of N quantum dots with N ranging from 1 to 7. Conductance oscillations as a function of gate voltage were seen for all gates in a single dot configuration and the capacitances of these gates to the dot were extracted. Temperature dependence of the conductance peak width was investigated. Current voltage measurements of the single dot system were made which allowed measurement of the total capacitance and the lead-to-dot capacitance. A double dot system was also investigated. For a pair of the weakly coupled quantum dots the period of conductance oscillations is essentially the same as for the single dot. As the coupling increases each peak splits into two peaks, and for a very strong coupling, when the two dots merge into one large dot, the peak period is the same as for a single large dot with twice the capacitance to the gate. Thesis Supervisor: Dimitri A. Antoniadis Title: Professor of Electrical Engineering