A high performance surface acoustic wave visible light sensor using novel materials: Bi₂S₃ nanobelts

Area of Science:

• Materials Science
• Nanotechnology
• Sensor Technology

Background:

• Low-dimensional Bismuth Sulfide (Bi$_{2}$S$_{3}$) materials offer excellent stability and fast response times for photodetector applications.
• Surface Acoustic Wave (SAW) devices are sensitive platforms for developing novel sensors.

Purpose of the Study:

• To develop a high-performance visible light sensor using Bi$_{2}$S$_{3}$ nanobelts integrated with SAW devices.
• To investigate the sensing mechanism and performance characteristics of the Bi$_{2}$S$_{3}$ nanobelt-based SAW sensor.

Main Methods:

• Fabrication of a SAW delay-line sensor on ST-cut quartz using photolithography.
• Preparation of Bi$_{2}$S$_{3}$ nanobelts via a hydrothermal process.
• Deposition of Bi$_{2}$S$_{3}$ nanobelts onto the SAW sensor using spin-coating.

Main Results:

• The fabricated SAW sensor exhibited a center frequency of 200.02 MHz.
• Under 625 nm visible light irradiation (170 μW cm$^{-2}$), the sensor showed a rapid frequency upshift of 7 kHz within 1 second.
• The observed frequency shift is attributed to the mass loading effect from oxygen desorption on the Bi$_{2}$S$_{3}$ nanobelts.

Conclusions:

• The Bi$_{2}$S$_{3}$ nanobelt-based SAW sensor demonstrates excellent performance for visible light detection.
• The sensor's fast response and stability make it a promising candidate for advanced photodetector applications.
• Visible light induces oxygen desorption from Bi$_{2}$S$_{3}$ nanobelts, leading to a measurable mass loading effect and frequency shift in SAW devices.