We report the electrical and optical comparison, in continuous wave regime, of two novel classes of silicon
photomultipliers (SiPMs) fabricated in planar technology on silicon P-type and N-type substrate respectively.
Responsivity measurements have been performed with an incident optical power from tenths of picowatts to hundreds of
nanowatts and on a broad spectrum, ranging from ultraviolet to near infrared (340-820 nm).
For both classes of investigated SiPMs, responsivity shows flat response versus the optical incident power, when a preset
overvoltage and wavelength is applied . More in detail, this linear behavior extends up to about 10 nW for lower
overvoltages, while a shrink is observed when the reverse bias voltage increases. With regards to our responsivity
measurements, carried out in the abovementioned spectral range, we have found a peak around 669 nm for the N-on-P
and a peak at 417 nm for the P-on-N SiPM. A physical explanation of the all experimental results is also provided in the