Center for Semiconductor Physics in Nanostructures
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Such study is significant in two aspects. One is to understand the electrical dipole behavior of single quantum nanostructures with different shapes. There were debates in literature on what is the dipole axis of an elongated nanostructure, along the short axis or along the long axis. Our experimental measurements of polarization of single quantum rods with different aspect ratios indicate that the electrical dipole is along the long axis for rod structure with aspect ratio larger than 2. In another aspect, the study of polarization properties of nanostructures can help the scope of applications of nanostructure in biological "labeling" or "tagging".
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Figure A1 : Synthesis (UA) - This shows the nature of the equipment used to grow CdSe Quantum dots and rods. |
Figure A2 : TEM of Deposited
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Figure A4: HRTEM Lattice Image of Rods (OU) - This shows a high Resolution TEM of rods grown at U. of Arkansas. Note the lattice imaging in both directions.
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Figure A3: Polarization Dependent PL (UA) - Polarization spectroscopy of single CdSe quantum rods with aspect ratio of about 2 (diameter ~4 nm, length ~8 nm). Both the emission and excitation show strong linear polarization dependence which follows a cosine square dependence on polarization angle. Measurements for a large number of single quantum rods all show similar behavior with extinction ratio above 90%.
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Figure A5: Size Dependent PL (UA) |
