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Updated: May 13, 2026

Fabrication of Fully Solution Processed Inorganic Nanocrystal Photovoltaic Devices
Published on: July 8, 2016
Microstructure and point defects in CdTe nanowires for photovoltaic applications
B L Williams1, D P Halliday, B G Mendis
1Stephenson Institute for Renewable Energy, Liverpool University, Liverpool, L69 7ZF, UK. b.l.williams@liverpool.ac.uk
Defects in gold-catalyzed cadmium telluride (CdTe) nanowires were analyzed. Annealing improved crystal quality, but processing for solar cells degraded performance, indicating potential for CdTe nanowire solar applications.
Area of Science:
- Materials Science
- Nanotechnology
- Semiconductor Physics
Background:
- Cadmium telluride (CdTe) nanowires are promising for solar cell applications.
- Gold (Au) is a common catalyst for vapour-liquid-solid (VLS) growth of semiconductor nanowires.
- Understanding defects is crucial for optimizing material properties.
Purpose of the Study:
- To critically evaluate defects in Au-catalyzed CdTe nanowires grown on polycrystalline underlayers.
- To investigate the impact of annealing and device processing on material quality.
- To assess the suitability of these nanowires for solar cell applications.
Main Methods:
- Low-temperature photoluminescence (PL) spectroscopy to analyze excitonic and defect-related emissions.
- Evaluation of structural defects such as stacking faults, polytypes, and twins.
- Analysis of the influence of annealing (nitrogen, oxidizing, reducing) on PL spectra.
- Correlation of defect incidence with nanowire growth axes.
Main Results:
- PL spectra were dominated by excitonic emission; above-gap emission was rarely observed.
- Acceptor bound exciton lines indicated monovalent metallic impurities (Ag, Cu, Na).
- Donor-acceptor-pair emission was attributed to gold (Au) catalyst contamination.
- Nitrogen annealing enhanced single crystal-like PL emission.
- Oxidizing/reducing anneals degraded PL emission.
- Stacking faults, polytypes, and twins correlated with growth axes (<111>, <112>, <110>), not annealing.
- Nanowire quality superior to polycrystalline films, but Au-related recombination is a concern.
Conclusions:
- Au-catalyzed CdTe nanowires exhibit high-quality excitonic emission.
- Annealing in nitrogen is beneficial, while solar cell processing anneals are detrimental.
- Structural defects are linked to growth orientation and not influenced by annealing.
- CdTe nanowires show promise for solar cells, but Au contamination requires further investigation.
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