ION-IMPLANTED GAAS FOR SUBPICOSECOND OPTOELECTRONIC APPLICATIONS

Ion implantation is shown to be able to shorten the carrier lifetime i n semi-insulating GaAs independent of the ion species, Although ion im plantation alone may shorten the lifetime to the order of femtoseconds , to obtain good resistivity and mobility annealing process is require d. furthermore, chemically active ions may complicate the recovery of resistivity, such as Si which may be activated as dopants during annea ling or O which creates additional deep levels. Optimum annealing temp erature was determined to be around 600 degrees C with carrier lifetim e still in the picosecond range but with mobility similar to 2000 cm(2 )/V . s. The shortening of the carrier lifetimes and electrical proper ties of these materials are correlated to the structural properties.