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-Hz/W at room temperature (at 1 V bias), while the tunnel detector has a ∼36∼36 times smaller detectivity but also ∼7500∼7500 times smaller standby power dissipation and a slightly higher signal-to-noise ratio.

Graphical abstractA novel chemically self-assembled nanowire infrared photodetector is demonstrated which works at room temperature with a normalized detectivity exceeding 107 Jones. It has a signal-to-noise ratio of 2:1 at room temperature which can be further increased to 7:1 by integrating the nanowire with a tunnel detector. This photodetector employs quantum mechanical wavefunction engineering to increase the signal-to-noise ratio at room temperature. It is rugged, cheap, reliable and mass-producible. A recent report states that millions of uncooled rugged infrared detectors will be required across the planet to monitor the effects of global warming. This detector is ideally suited for that task.Figure optionsDownload full-size imageDownload as PowerPoint slideRoom temperature current–voltage characteristic of a chemically self-assembled nanowire infrared photodetector.Highlights► Room temperature infrared detector implemented with self-assembled nanowires. ► Wavefunction engineering for high detectivity at room temperature. ► Tunneling photodetector for increased signal-to-noise ratio and low standby power dissipation. ► Frequency-selectivity is due to one-dimensional density of states in nanowires.