Open Access Nano Express

Increased conductance of individual self-assembled GeSi quantum dots by inter-dot coupling studied by conductive atomic force microscopy

Yifei Zhang, Fengfeng Ye, Jianhui Lin, Zuimin Jiang and Xinju Yang*

Author affiliations

State Key Laboratory of Surface Physics, Fudan University, Shanghai 200433, China

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Citation and License

Nanoscale Research Letters 2012, 7:278  doi:10.1186/1556-276X-7-278

Published: 31 May 2012

Abstract

The conductive properties of individual self-assembled GeSi quantum dots (QDs) are investigated by conductive atomic force microscopy on single-layer (SL) and bi-layer (BL) GeSi QDs with different dot densities at room temperature. By comparing their average currents, it is found that the BL and high-density QDs are more conductive than the SL and low-density QDs with similar sizes, respectively, indicating the existence of both vertical and lateral couplings between GeSi QDs at room temperature. On the other hand, the average current of the BL QDs increases much faster with the bias voltage than that of the SL QDs does. Our results suggest that the QDs’ conductive properties can be greatly regulated by the coupling effects and bias voltages, which are valuable for potential applications.

Keywords:
Conductance; Conductive atomic force microscopy; GeSi quantum dots; Coupling