Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas, 77843, United States.
Department of Materials Science and Engineering, Texas A&M University, College Station, Texas, 77843, United States.
Sci Rep. 2017 Jul 19;7(1):5836. doi: 10.1038/s41598-017-05711-4.
Chip-scale chemical detection is demonstrated by using mid-Infrared (mid-IR) photonic circuits consisting of amorphous silicon (a-Si) waveguides on an epitaxial barium titanate (BaTiO, BTO) thin film. The highly c-axis oriented BTO film was grown by the pulsed laser deposition (PLD) method and it exhibits a broad transparent window from λ = 2.5 μm up to 7 μm. The waveguide structure was fabricated by the complementary metal-oxide-semiconductor (CMOS) process and a sharp fundamental waveguide mode has been observed. By scanning the spectrum within the characteristic absorption regime, our mid-IR waveguide successfully perform label-free monitoring of various organic solvents. The real-time heptane detection is accomplished by measuring the intensity attenuation at λ = 3.0-3.2 μm, which is associated with -CH absorption. While for methanol detection, we track the -OH absorption at λ = 2.8-2.9 μm. Our monolithic Si-on-BTO waveguides establish a new sensor platform that enables integrated photonic device for label-free chemical detection.
采用由非晶硅(a-Si)波导组成的中红外(mid-IR)光子电路，实现了片上化学检测。该波导位于外延钛酸钡(BaTiO 3 ，BTO)薄膜上。高度取向 c 轴的 BTO 薄膜采用脉冲激光沉积(PLD)方法生长，具有从 λ=2.5μm 到 7μm 的宽透明窗口。波导结构通过互补金属氧化物半导体(CMOS)工艺制造，观察到了尖锐的基模。通过在特征吸收区域内扫描光谱，我们的 mid-IR 波导成功地实现了对各种有机溶剂的无标记监测。通过测量与-CH 吸收相关的 λ=3.0-3.2μm 处的强度衰减，实现了正庚烷的实时检测。而对于甲醇检测，我们跟踪 λ=2.8-2.9μm 处的-OH 吸收。我们的 Si-on-BTO 波导实现了单片集成，为无标记化学检测建立了新的传感器平台。
