Photo-active traps effect on photo-detection time of single electron photodetector

Abstract In this paper we report the photo-trapping effect of photogenerated charge in a few numbers of silicon nanocrystals (Si-NCs) embedded in SiO 2 layer tunnel oxide of small area single electron photodetector (Photo-SET or nanopixel). Using Current-Voltage measurements under illumination (photo-I–V) we find the photo-active traps effect in inversion zone at room temperature. Random Telegraphic Signal under illumination (photo-RTS analysis) confirms that is a photo-generated active trap inside into tunnel oxide layer ( E photo-act ∼ 0.2 eV ) and capture section: σ∼8.72 × 10 −17  cm 2 ). Moreover, an increasing about 10 pF in capacity’s values in the inversion region for inverse high voltage applied under photo-excitation at low temperature have been marked using photo-Capacitance-Voltage (photo-C–V) measurements. This result confirms the contribution of photo-active traps to better dots photo-charged. The increase of light excitation time-duration, increase the hysteresis width. At 100  μW optical power and 595  nm wavelength, the hysteresis width has their saturation for a 0,05V/s romp speed, and consequently, SiO 2 will not behave a dielectric, but as a metal. So we make think that total capacity of structure no more corresponds to the capacity related to the oxide, but to all structure capacity values. The nanopixel photo-detection time (∼400 s) estimated from the flat band evolution in time is affected by photo-active oxide traps presence.