表面電漿共振是存在於金屬與介電物質介面處的表面電磁波，近年來表面電漿共振的特性，已被大幅應用在生醫檢測技術。表面電漿共振生醫感測是屬於光學式的量測方式，對金屬/介電質界面的折射率變化具備超高的敏感度，藉此我們可以判定表面待測物質的濃度變化。 本研究以氮化物為介電質，搭配銀薄膜以形成表面電漿結構，並利用理論分析的方式，探究氮化物表面電漿結構在生醫感測上的應用潛力。與傳統常用的稜鏡相較，氮化物(GaN或InGaN)具備更高的折射率、更高的化學穩定度。而氮化銦鎵(InGaN)量子井所產生的光子，非常適合當作表面電漿效應的增益介質(Gain Medium)，可增加感測元件的靈敏度。此外，氮化物的磊晶方式，可輕易形成大面積分布的奈米結構，有助於產生單分子偵測所需的表面拉曼散射增強效應(surface enhanced Raman scattering, SERS)。我們利用模擬的方式，觀察其氮化物表面電漿的強度變化，並藉此說明氮化物表面電漿結構在生物檢測應用上的優勢。 ;Surface plasmon resonance (SPR) is the collective electron oscillation at the interface of metal and dielectric material. The SPR effect is highly sensitive to the change of surface refractive index, and therefore can be used to detect biomolecular binding events between the antibody and the antigen. In this research, we present theoretical analyses on the potential of nitride-based SPR structure in biosensing applications. The SPR effect is achieved with a GaN/InGaN/GaN quantum well and a thin Ag layer, and the change in surface refractive index is detected by the varied emission intensity from the quantum well. The nitride epilayers were grown with metal-organic chemical vapor deposition (MOCVD). The MOCVD technique can easily produce wafer-scale nanostructures that are suitable for single-molecule detection with the surface enhanced Raman scattering (SERS) effect. With the calculated dispersion curves and the penetration depths estimated by the finite-difference time-domain method, we demonstrate the advantages of this novel SPR biosensing structure, which are not attainable with the conventional Kretschmann configuration.
