Enhanced photo responsivity in nanowire-based photodetectors

In this work, simulations for a nanowire-based SOI-MOS photodetector are presented. It is proposed that, despite its smaller width, the nano-channel device has the potential to produce a higher photocurrent when biased appropriately to exploit the electrostatics possible in nanowires. There is an increase in photocurrent even though the dimensions of the investigated nanowires are too large to show an increase in optical dipole matrix element. All simulations are performed by solving the drift-diffusion equations self consistently with Poisson´s equation using a commercial simulator. A photo-enhanced sub-threshold slope in the NW-based photodetectors that is related to the device electrostatics and not the absorption coefficient is observed. Based on this observation we proposed new device geometry to further increase the photocurrent of the NW device in the accumulation mode. These advantages are in turn promising for higher density NW-based detector arrays for imaging applications.