Okanagan MicroElectronics and Gigahertz Applications (OMEGA) Laboratory, School of Engineering, University of British Columbia, Kelowna V1V 1V7, Canada.
Central European Institute of Technology, Brno University of Technology, Purkynova 123, Brno 61200, Czech Republic.
ACS Appl Mater Interfaces. 2023 Apr 12;15(14):18379-18390. doi: 10.1021/acsami.2c21877. Epub 2023 Apr 3.
Detection of visible light is a key component in material characterization techniques and often a key component of quality or purity control analyses for health and safety applications. Here in this work, to enable visible light detection at gigahertz frequencies, a planar microwave resonator is integrated with high aspect ratio TiO nanotube (TNT) layer-sensitized CdS coating using the atomic layer deposition (ALD) technique. This unique method of visible light detection with microwave-based sensing improves integration of the light detection devices with digital technology. The designed planar microwave resonator sensor was implemented and tested with resonant frequency between 8.2 and 8.4 GHz and a resonant amplitude between -15 and -25 dB, depending on the wavelength of the illuminated light illumination on the nanotubes. The ALD CdS coating sensitized the nanotubes in visible light up to ∼650 nm wavelengths, as characterized by visible spectroscopy. Furthermore, CdS-coated TNT layer integration with the planar resonator sensor allowed for development of a robust microwave sensing platform with improved sensitivity to green and red light (60 and 1300%, respectively) compared to the blank TNT layers. Moreover, the CdS coating of the TNT layer enhanced the sensor's response to light exposure and resulted in shorter recovery times once the light source was removed. Despite having a CdS coating, the sensor was capable of detecting blue and UV light; however, refining the sensitizing layer could potentially enhance its sensitivity to specific wavelengths of light in certain applications.
可见光检测是材料特性技术的关键组成部分，通常也是健康和安全应用中质量或纯度控制分析的关键组成部分。在这项工作中，为了在千兆赫兹频率下实现可见光检测，使用原子层沉积（ALD）技术将平面微波谐振器与高纵横比 TiO 纳米管（TNT）层敏化的 CdS 涂层集成在一起。这种基于微波的光检测与数字技术集成的独特可见光检测方法提高了光检测器件的集成度。设计的平面微波谐振器传感器采用了 8.2 到 8.4GHz 之间的谐振频率和-15 到-25dB 之间的谐振幅度，具体取决于光在纳米管上的照明波长。ALD CdS 涂层可将纳米管敏化至可见光谱中约 650nm 的波长，这是通过可见光谱学来表征的。此外，CdS 涂覆的 TNT 层与平面谐振器传感器的集成使得能够开发出一种稳健的微波传感平台，与空白 TNT 层相比，对绿光和红光的灵敏度分别提高了 60%和 1300%。此外，TNT 层的 CdS 涂层增强了传感器对光暴露的响应，并导致在光源移除后恢复时间更短。尽管有 CdS 涂层，传感器仍能够检测蓝光和 UV 光；然而，改进敏化层可能会在某些应用中提高其对特定波长光的灵敏度。
