Electron transport in quantum dot chains: Dimensionality effects and hopping conductance

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.

High Performance PbS Quantum Dot/Graphene Hybrid Solar Cell with Efficient Charge Extraction

“…Considering the relatively low conductivity of CQDs, − an intermediate pathway to quickly extract and transfer the photogenerated charge carriers is highly desirable to suppress exciton radiative recombination in the light-absorbing CQD layer. A number of conductive and semiconductive carbon-based materials such as fullerenes and carbon nanotubes have been demonstrated as efficient charge acceptor and/or transport layer in various optoelectronic semiconductor devices. − Among these functional nano carbon structures for efficient charge dissociation, graphene is one of the most promising candidates because of the lower energy level of graphene to the LUMO of PbS, extremely high electronic mobility (10 4 cm 2 /V·s at room temperature) as well as high transparency due to its atomic thickness (optical absorption of 2.3% per layer) minimizing interruption of the incident light absorption by the QDs. , Here we use SG flakes as an interlayer as illustrated in Figure a.…”

Interband Photoconductivity of Metamorphic InAs/InGaAs Quantum Dots in the 1.3–1.55-μm Window

“…However, such metamorphic structures are seldom studied in photoelectric measurements with a lateral geometry, where the photocurrent proceeds through in-plane transport of carriers across channels between two top contacts. Commonly, the QD layers along with the associated WL form these conductivity channels in the lateral geometry-designed GaAs-based structures [ 38 ]. Owing to this peculiar type of conductivity, QD photodetectors with the lateral transport are believed to have potential for a high photoresponsivity [ 39 , 40 ].…”

Quantum transport in a chain of quantum dots with inhomogeneous size distribution and manifestation of 1D Anderson localization

“…Notably, even the best synthesis method for colloidal QDs can produce QDs with a 3%-5% standard deviation in size 2 . Molecular beam epitaxy-grown QD arrays also exhibited a Gaussian statistical distribution in dot size 10 , 11 . While previous theoretical studies on QDs mainly examined the electronic properties of small QD systems 12 – 17 , a recent study examined the effect of impurity QDs on the electron transport in two-dimensional (2D) QD solids, in which the impurity QD was introduced as a perturbation to a periodic potential 18 .…”