Research Institute of Electronics, Shizuoka University, Hamamatsu 432-8011, Japan.
Department of Engineering, Graduate School of Integrated Science and Technology, Shizuoka University, Hamamatsu 432-8561, Japan.
Sensors (Basel). 2023 Jan 4;23(2):568. doi: 10.3390/s23020568.
This paper proposes a new optical biosensor composed of a silicon-on-insulator (SOI) p-n junction photodiode (PD) with a surface plasmon (SP) antenna. When the phase-matching condition between two lateral wavelengths of the diffracted light from the SP antenna and the waveguiding mode in the SOI PD is satisfied, we observe sharp peaks in the spectroscopic light sensitivity. Since the peak wavelength depends on the RI change around the SP antenna corresponding to the phase-matching condition, the SOI PDs with an SP antenna can be applied to the optical biosensor. The RI detection limit is evaluated in the measurements with bulk solutions, and 1.11 × 10 RIU (refractive index unit) can be obtained, which is comparable to that of a surface plasmon resonance (SPR) sensor, which is well known as a representative optical biosensor. In addition, the response for intermolecular bonds is estimated by the electromagnetic simulations using the finite-difference time-domain (FDTD) method to clarify its ability to detect biomolecular interactions. The results of this paper will provide new ground for high-throughput label-free biosensing, since a large number of SOI PDs with an SP antenna can be easily integrated on a single chip via an SOI complementary metal-oxide-semiconductor (CMOS) fabrication process.
本文提出了一种由具有表面等离子体 (SP) 天线的绝缘体上硅 (SOI) p-n 结光电二极管 (PD) 组成的新型光学生物传感器。当 SP 天线的衍射光的两个横向波长与 SOI PD 中的波导模式之间的相位匹配条件得到满足时，我们观察到光谱灵敏度出现尖锐峰值。由于峰值波长取决于对应于相位匹配条件的 SP 天线周围的 RI 变化，因此具有 SP 天线的 SOI PD 可应用于光学生物传感器。在使用体相溶液的测量中评估了 RI 检测限，并且可以获得 1.11×10 RIU（折射率单位），这与众所周知的代表性光学生物传感器表面等离子体共振 (SPR) 传感器相当。此外，通过使用有限差分时域 (FDTD) 方法的电磁模拟来估计分子间键的响应，以阐明其检测生物分子相互作用的能力。本文的结果将为高通量无标记生物传感提供新的基础，因为可以通过 SOI 互补金属氧化物半导体 (CMOS) 制造工艺很容易地将大量具有 SP 天线的 SOI PD 集成在单个芯片上。
