Long operating lifetime mid-infrared LEDs based on black phosphorus

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Physics

Background:

• Black phosphorus (BP) is a narrow bandgap semiconductor with potential for mid-infrared optoelectronics.
• BP-based devices offer high performance but suffer from poor air stability, limiting practical applications.
• Investigating passivation strategies is crucial for enhancing the durability of BP optoelectronic devices.

Purpose of the Study:

• To evaluate the impact of passivation on the operational lifetime of black phosphorus light-emitting diodes (BP LEDs).
• To determine the effectiveness of Al2O3 passivation and nitrogen packaging in improving device stability.
• To extrapolate the long-term operational performance of protected BP LEDs.

Main Methods:

• Atomic layer deposition (ALD) of Al2O3 for passivation.
• Nitrogen packaging using ultra-violet (UV) curable resin sealing.
• Accelerated life testing at room temperature to assess device lifetime.

Main Results:

• BP LEDs without passivation degrade within seconds.
• Al2O3 passivation and nitrogen packaging significantly extend device lifetime.
• Accelerated testing projects an operational half-life of approximately 15,000 hours at room temperature for protected BP LEDs with an initial power density of 340 mW/cm2.

Conclusions:

• Simple and scalable passivation and packaging technologies can render black phosphorus optoelectronics highly robust.
• The findings have significant implications for the practical implementation of BP in mid-infrared applications.
• Efficient and stable mid-infrared optoelectronic devices based on black phosphorus are achievable.