Quantum Dot Chains...

FIG. 2.
(a) 5×5 μm 2 AFM topography image of QDC sample C. The chains are aligned along the [1¯10] crystallographic direction; (b) 1×1 μm 2 AFM image of the same sample; statistical distribution with Gaussian fits of the (c) QD height; (d) distance between QDs, d in , within the chains (peak-to-peak) measured along [1¯10] direction; and (e) distance between neighboring chains, d bc , measured peak-to-peak; (f) hall bar structure used for electrical characterization with a channel width of 25  μm.

ABSTRACT

Detailed experimental and theoretical studies of lateral electron transport in a system of quantum dot chains demonstrate the complicated character of the conductance within the chain structure due to the interaction of conduction channels with different dimensionalities. The one-dimensional character of states in the wetting layer results in an anisotropic mobility, while the presence of the zero-dimensional states of the quantum dots leads to enhanced hopping conductance, which affects the low-temperature mobility and demonstrates an anisotropy in the conductance. These phenomena were probed by considering a one-dimensional model of hopping along with band filling effects. Differences between the model and the experimental results indicate that this system does not obey the simple one-dimensional Mott's law of hopping and deserves further experimental and theoretical considerations.

Journal of Applied Physics: Electron Transport in Quantum Dot Chains