(170b) Development of Non-Oxide Silicon Nanowire Field Effect Transistors for Selective Gas Detection

We are currently developing a silicon nanowire field effect transistor sensor array to improve the sensitivity and diagnostic yield of our current clinical chemiresistors. The silicon nanowire has a natural passive oxide layer which causes trap states and sensing inaccuracies. Modifications, done after removing the oxide, are desirable for improved sensitivity and gas selectivity.

        Silicon nanowires were modified with different C₃ alkyl groups: propyl (Si-CH2-CH2-CH3), propenyl (Si‑CH=CH‑CH3), and propynyl (Si-C≡C-CH3) surface groups. We will present the most sensitive and selective C₃ alkyl surface modifications in detecting 12 separate analytes (volatile organic compounds) relevant in breath detection for disease diagnosis. In addition, the specificity of 12 separate gas analytes, using discriminant analysis, will also be presented. Each modification provides a different sensing mechanism, leading to variations in sensitivity, stability, and analyte selectivity. We will demonstrate that a variety of surface modifications in a sensor array leads to higher selectivity of the 12 analytes due to different sensing mechanisms in the discriminant analysis. In conclusion, the alkyl-modified sensor shows promise as a selective clinical sensor for specific analyte detection.