The influence of 5 MeV ⁷Li ion implantation into the high-field region of SiC and Silicon photodiodes on the optoelectronic device characteristics has been investigated. While the in situ monitoring of the radiation-induced currents, measured during the high-energy ion irradiation, showed comparable degradation, the comparison of the electrical characteristics of irradiated and non-irradiated samples showed a more complicated picture. In the case of the SiC photodiodes no degradation of the forward dark current-voltage characteristics has been found, while in the case of the Silicon pin-diode a strong lowering of the threshold voltage and the increase of the recombination current is observed. Regarding the reverse bias characteristics, a more than two orders of magnitude current increase is observed for the Silicon photodiode, while the reverse bias current for the SiC device even decreased slightly. Regarding our application in our nuclear astrophysics experiment, the influence of the radiation with light energetic particles, similar to 7Be on the diode reverse bias stability is crucial and again SiC devices seem to be the right host material for this purpose.