Integrating ultraviolet sensing and memory functions in gallium nitride-based optoelectronic devices

Area of Science:

• Materials Science
• Optoelectronics
• Solid-State Physics

Background:

• Optoelectronic devices aim to mimic the human visual system but lack persistent image memory.
• Storing ultraviolet (UV) images is crucial for capturing invisible visual information.
• Existing technologies struggle to integrate sensing and memory functions for optical data.

Purpose of the Study:

• To develop a multi-level UV optoelectronic memory device with integrated sensing and storage capabilities.
• To enhance the retention of optical image information after stimulus removal.
• To explore the potential of UV optoelectronic memory for artificial vision applications.

Main Methods:

• Fabrication of a gallium nitride (GaN) based multi-level UV optoelectronic memory.
• Integration of SiO2 side-gates to extend photo-generated carrier lifetime.
• Utilizing threshold voltage and ON-state current for dual-mode UV signal storage.

Main Results:

• The GaN device demonstrated robust UV sensing and memory with retention time > 4 × 10^4 s and > 1 × 10^5 programming/erasing cycles.
• Achieved five distinct storage states by adjusting gate voltage, with excellent retention and tunable erasure times.
• Successfully captured and stored UV images for over 7 days using an integrated GaN optoelectronic memory array.

Conclusions:

• The developed GaN optoelectronic memory successfully integrates UV sensing and long-term data storage.
• The device exhibits high performance, robustness, and multi-level storage capabilities for UV visual information.
• This advancement holds significant potential for future artificial vision systems requiring prolonged optical memory.