ULTRAFAST CARRIER TRAPPING AND HIGH-RESISTIVITY OF MEV ENERGY ION-IMPLANTED GAAS

Semi-insulating GaAs wafers were implanted with MeV As, Ga, O or Si io ns at doses ranging from 1 x 10(14) to 5 x 10(16) cm(-2). Their struct ural properties were studied by electron microscopy and the Rutherford backscattering-channeling. Time resolved photoluminescence, electrica l conductivity and the Hall effect were used to determine carrier life time and electrical properties of the material. Annealing of the sampl es at 600 degrees C Zed to the recovery of transport in conduction ban d. The As, Ga and O implanted samples became semi-insulating, while th e Si implanted samples were n-type. Carrier trapping times were short, shorter than 1 ps for the highest dose used. Models explaining tile f ast photocarrier decay are discussed.