Development of high-sensitivity ambient light sensor based on cadmium sulfide-deposited surface acoustic wave sensor
| Autor: | Byeong Kwon Ju, Jin Woo Lee, Jong Woo Kim, Jinkee Hong, Kunnyun Kim, Yeon Hwa Kwak, Byungmoon Lee |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Materials science
Lithium niobate Photodetector 02 engineering and technology 01 natural sciences chemistry.chemical_compound 0103 physical sciences Electrical and Electronic Engineering Thin film Instrumentation 010302 applied physics business.industry Surface acoustic wave Metals and Alloys 021001 nanoscience & nanotechnology Condensed Matter Physics Cadmium sulfide Surfaces Coatings and Films Electronic Optical and Magnetic Materials Transducer chemistry Optoelectronics Surface acoustic wave sensor 0210 nano-technology business Coupling coefficient of resonators |
| Zdroj: | Sensors and Actuators A: Physical. 293:145-149 |
| ISSN: | 0924-4247 |
| DOI: | 10.1016/j.sna.2019.03.048 |
| Popis: | A highly sensitive ambient light sensor based on surface acoustic waves (SAWs) was investigated. The ambient light SAW sensor is fabricated by depositing sensitive film and its resonant frequency shift was calculated in response to a change in light intensities. The resonant frequency is generated between the piezoelectric substrate and a specifically designed transducer, which is usually called interdigitated transducer (IDT). The IDT design was determined to exhibit the resonant frequency at 244.5 MHz by considering the sensor size and fabrication process. We fabricated our ambient light SAW sensor by using a cadmium sulfide (CdS) thin film as a sensing material. Absorbance spectra of CdS thin film in visible light region were investigated. Then the lithium niobate (LiNbO3) substrate is adopted as a substrate due to its high coupling coefficient. Fabrication of CdS thin films was conducted by thermal evaporator and common lithography process including lift-off. To increase the sensitivity of the sensor, we focused on increasing the thickness and area of the sensitive film. As a result, the sensitivity increased by approximately three times when the area doubled. |
| Databáze: | OpenAIRE |
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