This work is devoted to study photoelectric properties of GaP nanowires (NWs) modified by carbon nanodots (CDs). Photoelectric properties of samples were studied by electrochemical impedance spectroscopy (EIS) over a wide frequency range. Impedance spectra were shown in Nyquist plot in dark conditions and under ultraviolet (UV) illumination allowed to evaluate changes of active resistance of the NWs before and after modification with the CDs, in terms of resistance response. Temperature evolution of GaP NWs impedance spectra in the range from 25 to 205 °C before and after the modification was studied also in dark and UV conditions. The largest response reached 25% and was detected at room temperature in modified NWs. Heating of the samples lead to decreasing of response down to 25% with modified NWs, whereas for GaP the response did not exceed 13%. The result is interesting for processing of photosensitive detectors working in room temperature.