Columnar nitrogen-doped ZnO nanostructured thin films obtained through atomic layer deposition

Area of Science:

• Materials Science
• Nanotechnology
• Solid State Chemistry

Background:

• Zinc oxide (ZnO) is a versatile semiconductor with applications in electronics and optoelectronics.
• Developing nanostructured and doped ZnO thin films is crucial for enhancing its properties.
• Nitrogen doping is a promising strategy to modify ZnO's electronic and optical characteristics.

Purpose of the Study:

• To develop nitrogen-doped nanostructured ZnO thin films using a sequential atomic layer deposition and hydrothermal process.
• To investigate the impact of nitrogen doping concentration on the physicochemical properties of ZnO thin films.
• To establish a viable method for producing high-quality N-doped ZnO nanostructured thin films.

Main Methods:

• Atomic Layer Deposition (ALD) for growing a ZnO seed layer on a Si (100) substrate using diethylzinc (DEZn) and H2O.
• Microwave-assisted solvothermal process for growing columnar ZnO nanostructures using Zn(NO3)2 and hexamethylenetetramine (HMTA).
• Structural and chemical characterization using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Raman, and UV-Vis spectroscopy.

Main Results:

• Nitrogen-doped ZnO films exhibited textured wurtzite-like structures.
• The preferential growth plane shifted from (002) to (100) with increasing nitrogen precursor concentration.
• A reduction in the bandgap was observed for nitrogen-doped ZnO films compared to undoped ZnO.
• The developed methodology successfully produced high-quality N-ZnO nanostructured thin films.

Conclusions:

• The sequential ALD and microwave-assisted solvothermal method is effective for fabricating N-doped nanostructured ZnO thin films.
• Nitrogen doping significantly influences the structural and optical properties of ZnO, including crystal orientation and bandgap.
• The findings provide a foundation for advanced applications of N-doped ZnO nanomaterials.