The luminescent and structural properties of GeOx thin films and GeO/SiO2 multilayer heterostructures, irradiated with 167 MeV Xe ions with fluencies up to 1013 cm−2 , were studied. We report strong photoluminescence in visible range at room temperature, which is most probably due to Ge-related defect-induced radiative transitions. And infrared luminescence bands (from ~0.8 eV to ~1.2 eV) were observed in as-deposited and irradiated structures, which can be related to defects or defects complexes in GexSiyO2 glass and partially in Si substrate. It was shown that swift heavy ion irradiation does not lead to the expected phase separation of germanium suboxide into germanium nanoclusters and GeO2, but causes the intermixing of GeO/SiO2 layers with the formation of Ge-O-Si bonds.
In the present study, we experimentally examined the effect of swift Хе ion irradiation of multilayer structures involving ultrathin alternating layers of SiO2 and amorphous hydrogenated silicon (α-Si:H), and subsequent isochronal anneals of such structures, on their properties. It is shown that the action of swift heavy ions on Si/SiO2 multilayer structures leads to the formation of Si nanoclusters. In the latter case, the multi-layer structure of the samples was retained, and the ordering of nanoclusters along ion tracks was observed. The irradiation produces nuclei which, during subsequent anneals, facilitate the formation of Si nanocrystals (Si NCs) in the dielectric layer. In the multi-layer metal-oxide-semiconductor (MOS) structures with Si NCs embedded in the dielectric matrix, a phenomenon of bipolar resistive switching was observed. On increasing the number of NC layers, during the on-off process intermediate metastable states were manifested. This observation may prove important for realization of intermediate resistance values (multi-bit data storage) and for the development of additive neuromorphic systems.