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Polarization surface-charge density of single semiconductor quantum rods
Rishikesh Krishnan1, Megan A Hahn, Zhiheng Yu
1Department of Electrical and Computer Engineering, University of Rochester, Rochester, New York 14627, USA.
Physical Review Letters
|July 13, 2004
Summary
Single cadmium selenide quantum rods (CdSe QRs) unexpectedly exhibit permanent surface charge density due to slight structural asymmetry. This finding may hinder the development of new CdSe QR-based devices.
Area of Science:
- Materials Science
- Nanotechnology
- Condensed Matter Physics
Background:
- Cadmium selenide quantum rods (CdSe QRs) are nanomaterials with potential applications in various devices.
- The expected properties of well-shaped CdSe QRs include a significant dipole moment.
- Understanding surface charge is crucial for predicting and controlling nanomaterial behavior.
Purpose of the Study:
- To investigate the surface charge properties of individual CdSe quantum rods.
- To determine the origin of any observed surface charge.
- To assess the implications of these findings for device applications.
Main Methods:
- Utilized electrostatic force microscopy (EFM) to probe the surface charge of single CdSe QRs.
- Analyzed the relationship between particle geometry and internal electric polarization.
Main Results:
- Single CdSe QRs were found to possess a permanent polarization surface-charge density.
- This unexpected surface charge arises from a slight misalignment between the QR's sides and its internal electric polarization.
- No significant dipole moment was detected, contrary to expectations for CdSe QRs.
Conclusions:
- The presence of permanent surface charge on CdSe QRs is an inherent property, not an artifact of poor shape.
- This surface charge characteristic could present challenges for the integration of CdSe QRs into novel electronic and photonic devices.
- Further research is needed to mitigate or utilize this surface charge for technological advancements.