Developing high-transmittance heterojunction diodes based on NiO/TZO bilayer thin films

Area of Science:

• Materials Science
• Condensed Matter Physics
• Semiconductor Devices

Background:

• Nickel oxide (NiO) and titanium-doped zinc oxide (TZO) are crucial materials in semiconductor research.
• Heterojunction diodes are fundamental components in various electronic and optoelectronic devices.
• Achieving high transmittance and well-defined p-n junctions is essential for advanced applications.

Purpose of the Study:

• To fabricate and characterize p(NiO)-n(TZO) heterojunction diodes with high transmittance.
• To investigate the structural, optical, and electrical properties of NiO and TZO thin films.
• To analyze the performance of the NiO/TZO heterojunction devices.

Main Methods:

• Radio frequency magnetron sputtering for depositing NiO and TZO thin films on glass substrates.
• Scanning electron microscopy (SEM) for surface morphology analysis.
• X-ray diffraction (XRD) for structural characterization.
• UV-visible spectroscopy for optical properties.
• Hall effect analysis for electrical properties.
• Current-voltage (I-V) analysis for device performance.

Main Results:

• NiO/TZO heterojunction devices exhibited only (111) NiO and (002)/(004) TZO diffraction peaks, indicating good c-axis orientation of TZO.
• Successful formation of p-n junction characteristics was confirmed via I-V analysis for TZO deposition powers of 100, 125, and 150 W.
• The electrical transport in the NiO/TZO heterojunction diode was found to be dominated by space-charge limited current theory.

Conclusions:

• High transmittance p(NiO)-n(TZO) heterojunction diodes were successfully fabricated using radio frequency magnetron sputtering.
• The structural and electrical properties indicate the potential of these heterojunctions for optoelectronic applications.
• The space-charge limited current theory provides a model for understanding the device's electrical behavior.