Strategy for One-Step Optimization of Metal Oxide Passivating Contact Materials for Si Heterojunction Solar Cells...

Area of Science:

• Materials Science
• Semiconductor Physics
• Renewable Energy

Background:

• Silicon heterojunction (SHJ) solar cells require complex multi-step processes for optimal performance.
• Achieving efficient passivation and carrier selectivity is crucial for high-efficiency SHJ solar cells.

Purpose of the Study:

• To develop a novel, simplified fabrication method for SHJ solar cells.
• To tailor the properties of metal oxide contact materials and their interfaces with silicon in a single step.

Main Methods:

• A one-step oblique-angle reactive sputtering technique was employed.
• Angle-dependent ion bombardment was used for in situ ion-assisted oxidation of vanadium oxide (V₂O_5-x) on silicon.
• Monte Carlo simulations and time-of-flight secondary ion mass spectrometry (TOF-SIMS) were used to analyze the interface.

Main Results:

• Depositing V₂O_5-x at 80° yielded a phase-pure, high-work-function film ideal for passivation and improved the underlying silicon oxide layer.
• An intermediate angle of 40° produced a mixed-phase V₂O_5-x film without degrading interfacial quality.
• The deposition angle was found to control V-Si-O intermixing depth, significantly impacting interfacial properties.

Conclusions:

• The developed one-step, room temperature sputtering method effectively replaces multi-step chemical pre-treatments.
• This technique offers a viable route for integrating carrier-selective metal oxides in SHJ solar cells.
• The method has potential applications in other silicon-based electronic and optoelectronic devices.