Indium tin oxide nanowhisker morphology control by vapour-liquid-solid glancing angle deposition

Area of Science:

• Materials Science
• Nanotechnology
• Thin Film Deposition

Background:

• Indium tin oxide (ITO) is crucial for transparent conductive films.
• Existing ITO nanowhisker growth methods lack precise control over morphology and density.
• Need for advanced fabrication techniques to tailor ITO nanostructures for specific applications.

Purpose of the Study:

• To introduce and characterize a novel VLS-GLAD growth technique for indium tin oxide (ITO) nanowhiskers.
• To investigate the influence of growth parameters, particularly large deposition angles, on nanowhisker morphology.
• To evaluate the performance of the resulting nanostructured films as transparent conductive oxides.

Main Methods:

• Utilized a hybrid self-catalyzed vapor-liquid-solid (VLS) growth and glancing angle deposition (GLAD) technique.
• Controlled nanowhisker morphology by manipulating deposition angle, flux rate, nominal pitch, and substrate temperature.
• Analyzed nanowhisker structure and density through spatial modulation of the growth flux.
• Measured sheet resistance and transmission of the fabricated films.

Main Results:

• Achieved enhanced control over nanowhisker feature size, spacing, and density.
• Demonstrated that large deposition angles in GLAD amplify the effects of VLS parameters on morphology.
• Identified specific growth conditions influencing trunk width, branching, and orientation.
• Fabricated hybrid nanostructured films with high surface area nanowhiskers on a conductive ITO film.

Conclusions:

• The VLS-GLAD technique provides superior control over ITO nanowhisker fabrication compared to traditional methods.
• Optimized growth conditions enable tailoring of nanowhisker morphology for specific device requirements.
• The developed nanostructured films are highly suitable for transparent conductive electrode applications.