矽奈米線P-I-N二極體於生物感測之應用

Abstract

本論文利用電子束微影，製作出寬約110奈米、厚約45奈米之矽奈米線P-I-N二極體，並應用於生物感測。此元件具有良好的光電性質; 填充因子~73%、開路電壓~ 0.46V、短路電流 ~ 4.25 mA/cm^2，當使用顯微鏡光源照射時，在零偏壓處即可偵測出光電流，其開關比大約在10^3~10^4。同時利用自組裝技術(Self-assembly technique)在元件表面修飾Amino Propyl Triethoxy Silane (APTES) 與帶負電金奈米粒子、Biotin-Streptavidin來測試元件之分子感測靈敏度。另外，我們使用銀染技術將修飾在元件表面上的金奈米粒子放大加強遮光效果，進而增加在低濃度時的感測靈敏度。當元件表面接上不同之生物分子時，對於P-I-N二極體生物感測器產生遮光的效應，影響元件之光電流強度，偵測極限最低可以到達128 pM。由實驗結果看出，矽奈米線P-I-N二極體為一相當具有潛力的生物分子感測元件。

In this thesis, silicon nanowire P-I-N diode array with width of ca. 110 nm and thickness of 45 nm was successfully fabricated using e-beam lithography for biosensing applications. The characteristics of silicon nanowire P-I-N diode has been characterized and shown good photoelectric properties; a fill factor of ca.72%、a Voc value of ca.0.51 V and a Js of ca. 11.2 mA/cm2. When illuminated microscope light sources, photocurrent can be easily detected at zero bias and the on/off current ratio reached 103 to 104. Then, amino Propyl Triethoxy Silane (APTES) and gold nanoparticles, Biotin-Streptavidin were used for surface modifications to test the device sensitivity on surface bindings. In addition, silver staining on gold nanoparticles was adopted to enhance sensitivity via the shading effect, which increases sensitivity in low concentration. Results showed that the lowest detection limit can reach ca. 128 pM of AuNps under assistance of silver stain. The silicon nanowire P-I-N diode has shown promising potential as a bio-sensing device.