Fabrication and characterization of a multiple gate nanowire FET for detecting spatially distributed molecular charges

We investigate a multiple-gate GaAs-based nanowire field-effect transistor (FET) for detecting spatially distributed molecular charges. Spatial resolution is implemented to the nanowire by arranging narrow metal gate array. In this device the molecule charge position and the metal gate position are correlated through capacitive coupling between the molecule and a metal gate. Then a molecule charge in the gate periphery with appropriate gate biasing selectively reflects in the nanowire current. To demonstrate our concept, we fabricate a GaAs-based nanowire FET having a 50-nm-length Schottky gate array with 50-nm interval and investigate to arrange the charged molecules at arbitrary position using Tetraphenylporphyrin (TPP).