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Synthesis of Hierarchical ZnO/CdSSe Heterostructure Nanotrees
Published on: November 29, 2016
Defect studies of ZnSe nanowires
U Philipose1, Ankur Saxena, Harry E Ruda
1Centre for Nanotechnology, University of Toronto, 170 College Street, Toronto, ON, M5S 3E4, Canada.
Nanotechnology
|July 7, 2011
Summary
A new thermodynamic model estimates defect concentration in zinc selenide (ZnSe) nanowires. Positron annihilation spectroscopy validated model predictions, correlating structural and optical findings with defect levels.
Area of Science:
- Materials Science
- Nanotechnology
- Semiconductor Physics
Background:
- Zinc selenide (ZnSe) nanowires exhibit defects like stacking faults and twinning, impacting their optical properties.
- Defect-related emission is a significant factor in the photoluminescence spectra of ZnSe nanowires.
Purpose of the Study:
- To develop a thermodynamic model for estimating defect concentration in ZnSe nanowires.
- To explain experimental findings related to defects under varying selenium (Se) vapor pressure.
- To validate the model using positron annihilation spectroscopy and other characterization techniques.
Main Methods:
- Development of a simple thermodynamic model.
- Growth of ZnSe nanowires under controlled Se vapor pressure.
- Positron annihilation spectroscopy (PAS) for defect characterization.
- Photoluminescence (PL) spectroscopy for optical analysis.
- Structural characterization techniques.
Main Results:
- The thermodynamic model successfully estimates defect concentration in ZnSe nanowires.
- Positron annihilation spectroscopy provided the first defect characterization for nanowires, supporting the model's predictions.
- Experimental results from structural and optical characterization align with the model's predictions.
- Excess Se vapor pressure leads to the formation of Se nodules on nanowire sidewalls.
Conclusions:
- The developed thermodynamic model is effective for predicting defect concentrations in ZnSe nanowires.
- Positron annihilation spectroscopy is a viable technique for nanowire defect analysis.
- Understanding defect formation is crucial for controlling ZnSe nanowire properties.
- Optimizing Se vapor pressure is essential to prevent unwanted Se precipitation during vapor-liquid-solid growth.
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