Silicon photodetectors have a limited response in the visible range. However, the silicon technology is currently the most important. Then there is the need to develop silicon sensors that are able to detect radiation in different ranges. In this paper, a sensor, that uses Si nano-particles, sensible in the whole range form 200 to 1100 nm is characterized in both DC and AC signal. A discussion is done that relates the sensibility of the sensor with the SRO characteristics.