Surface Defines the Properties: Colloidal Bi2Se3 Nanosheets with High Electrical Conductivity
Journal of Physical Chemistry C 125, 6442 (2021).
C. Bauer, R. Lesyuk, M. Samadi Khoshkhoo, C. Klinke, V. Lesnyak, and A. Eychmuller.
https://doi.org/10.1021/acs.jpcc.1c00491

We investigated the colloidal synthesis of Bi2Se3 nanosheets in ethylene glycol with the goal of increasing their lateral dimensions while keeping their thickness within a few nanometers. The influence of proton-donating sulfuric acid was found to be a triggering factor that promoted the lateral growth of up to 10 μm, whereas the thickness remained in the range 10-12 nm. The lateral size distribution was further optimized by size-selective precipitation enabling individual contacting of the nanosheets by electron-beam lithography. Electrical characterization of individually contacted nanosheets revealed a metal-like temperature dependence of the resistivity and values of the specific conductivity in the range of 470 S/cm at room temperature and 880 S/cm at 5.5 K, which is attributed to the surface-induced off-stoichiometry. The presented colloidal nanosheets can potentially serve as a platform for further studies on topologically nontrivial surface states and arising quantum phenomena in two-dimensional systems.

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Surface Defines the Properties: Colloidal Bi2Se3 Nanosheets with High Electrical Conductivity
Journal of Physical Chemistry C 125, 6442 (2021).
C. Bauer, R. Lesyuk, M. Samadi Khoshkhoo, C. Klinke, V. Lesnyak, and A. Eychmuller.
https://doi.org/10.1021/acs.jpcc.1c00491

We investigated the colloidal synthesis of Bi2Se3 nanosheets in ethylene glycol with the goal of increasing their lateral dimensions while keeping their thickness within a few nanometers. The influence of proton-donating sulfuric acid was found to be a triggering factor that promoted the lateral growth of up to 10 μm, whereas the thickness remained in the range 10-12 nm. The lateral size distribution was further optimized by size-selective precipitation enabling individual contacting of the nanosheets by electron-beam lithography. Electrical characterization of individually contacted nanosheets revealed a metal-like temperature dependence of the resistivity and values of the specific conductivity in the range of 470 S/cm at room temperature and 880 S/cm at 5.5 K, which is attributed to the surface-induced off-stoichiometry. The presented colloidal nanosheets can potentially serve as a platform for further studies on topologically nontrivial surface states and arising quantum phenomena in two-dimensional systems.

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Involved Scientists