Star shaped triple quantum dot with charge detection

We present transport measurements on a lateral triple quantum dot made with local anodic oxidation on a GaAs/AlGaAs heterostructure. The device is formed in a star like geometry with each dot connected to the other two. Three leads are used to measure the conductance of the device simultaneously via different paths. Furthermore a quantum point contact is built in close vicinity to the dots. Thus the charge on the dots can be detected. In charge stability diagrams clear anticrossings are visible when states of two dots come into resonance forming triple points. Using a third gate resonances of all three dots can be established where three triple points meet in the so-called quadruple points. With one lead used as the source contact and the other two used as two different drain contacts signatures of the three dots are visible in transport via both transport paths.