We have investigated the deterioration of field effect transistors based on twodimensional materials due to irradiation with swift heavy ions. Devices were prepared with exfoliated single layers of MoS2 and graphene, respectively. They were character
ized before and after irradiation with 1.14 GeV U228+2 ions using three different fluences. By electrical characterization, atomic force microscopy and Raman spectroscopy we show that the irradiation leads to significant changes of structural and electrical properties. At the highest fluence of 4 x 102^11 ions/cm^2, the MoS2 transistor is destroyed, while the graphene based device remains operational, albeit with an inferior performance.
