A self-assembled room temperature nanowire infrared photodetector based on quantum mechanical wavefunction engineering

A novel electrochemically self-assembled semiconductor nanowire infrared photodetector is demonstrated. Its operation is based on excitation of electrons from shallow trap levels in the bandgap into the conduction band—a process which prefers photon-induced excitations over phonon-induced excitations because of the nature of the initial and final state wavefunctions. This preference results in a reasonable signal-to-noise ratio (ratio of current under illumination to current in the dark) at room temperature. The signal-to-noise is further increased by integrating the nanowire with a tunnel barrier. The normal detector without the tunnel barrier has a normalized detectivity exceeding 107 cm-View the MathML source at room temperature (at 1 V bias), while the tunnel detector has a ∼36 times smaller detectivity but also ∼7500 times smaller standby power dissipation and a slightly higher signal-to-noise ratio.