Comprehensive Optoelectronic Study of Copper Nitride: Dielectric Function and Bandgap Energies

Area of Science:

• Materials Science
• Solid State Physics
• Optoelectronics

Background:

• Copper nitride (Cu3N) is an emerging eco-friendly thin-film semiconductor.
• It has potential applications in storage devices, microelectronics, photodetectors, and photovoltaic cells.
• Previous research highlights the need for detailed optoelectronic characterization.

Purpose of the Study:

• To conduct a detailed optoelectronic study of Cu3N thin films.
• To investigate the optical properties across the UV-Vis-NIR spectral range.
• To determine the bandgap energies for potential device applications, particularly photovoltaics.

Main Methods:

• Reactive RF-magnetron sputtering was used to grow Cu3N thin films under pure N2.
• Multi-angle spectroscopic ellipsometry, broadband transmission, and reflection measurements were employed.
• A stratified geometrical approach and a combined Tauc-Lorentz, Gaussian, and Drude dispersion model were used to analyze optical properties.

Main Results:

• The Cu3N films exhibited a cubic anti-ReO3 type structure with preferential (100) orientation.
• The complex dielectric function was precisely determined, revealing distinct electronic transitions.
• Indirect bandgaps of 1.83-1.85 eV and direct bandgaps of 2.38-2.39 eV were accurately extracted.

Conclusions:

• This study provides an extensive characterization of Cu3N thin films.
• The determined bandgap energies are suitable for solar applications, indicating significant potential for photovoltaic devices.
• The findings pave the way for optimized device applications and broader utilization of Cu3N.