Quantum-wired MOSFET photodetector fabricated by conventional photolithography on SOI substrate

NMOSFETs with a sub-30 nm-wide silicon quantum wire were fabricated and its electrical and optical characteristics were investigated. The silicon quantum wire was obtained by conventional photolithography with the help of anisotropic wet etching and reactive ion etching on a silicon-on-insulator substrate. Step-like conductance versus gate voltage, which is an evidence of one-dimensional electron motion, has been observed even at temperatures below 173 K. A maximum photo-responsivity of the quantum MOSFET was larger than 1×10² A/W at a wavelength of 632.8 nm. These features make this transistor feasible for applications to highly sensitive photodetectors.