GaN-Based High-Contrast Grating for Refractive Index Sensor Operating Blue-Violet Wavelength Region

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Optical refractive index (RI) sensors are vital for Internet of Things (IoT) applications, including immunosensing, disease detection, and blood mapping, due to their versatility, compact size, and chemical stability.
• Developing sensors with simple systems and high chemical stability remains a key challenge for widespread adoption in IoT environments.

Discussion:

• A Gallium Nitride (GaN)-based high-contrast grating (HCG) sensor was designed and fabricated on a GaN-film grown on a c-plane sapphire substrate.
• Numerical electromagnetic field calculations were employed to analyze light behavior within the GaN-HCG, providing a deep understanding of the sensing mechanism.
• The sensor demonstrated the capability to detect minute RI changes as small as 1.71 × 10^-3.

Key Insights:

• The fabricated GaN-HCG sensor exhibits high sensitivity and exceptional chemical stability.
• A simplified surface normal irradiation system facilitates easy operation and integration.
• The sensor's design offers a robust platform for precise RI measurements.

Outlook:

• The developed GaN-HCG sensor's simple system and high chemical stability are well-suited for diverse RI sensing applications within the IoT society.
• Future research could explore integration into portable diagnostic devices and environmental monitoring systems.
• Further optimization of the GaN-HCG structure may lead to even higher sensitivity and broader application scope.