Coupling characteristics of semiconductor coupled quantum dots in coulomb blockade regime

Coupled quantum dots in series have been realized in two dimensional electr on gas (2DEG) in GaAs/AlGaAs heterostructures using the surface gate, and t ransport measurements have been performed at the dilution refrigerator temp erature. The electrical transport was found to be determined by the Coulomb blockade and the resonant tunneling. The energy width of the resonant peak can be smaller than the thermal energy when two dots are sufficiently isol ated. The charge stability diagram, by changing two gates attached to each dot, was measured for weak and strong coupling conditions. The width of the current resonant peak changed significantly as the coupling was increased, while the capacitive coupling did not change so much. The experimental res ult was analyzed using a simple capacitance model.