ULTRAFAST CARRIER TRAPPING IN OXYGEN-DOPED METAL-ORGANIC VAPOR-PHASE EPITAXY GAAS

We have experimentally investigated the ultrafast carrier dynamics in GaAs grown by metal-organic vapor phase epitaxy with an oxygen precurs or. Using a time-resolved reflection ellipsometric technique, we measu red the carrier-induced refractive and absorptive index changes as a f unction of oxygen and aluminum doping concentrations, The free carrier trapping time is inversely proportional to the aluminum-oxygen based complex concentration and can be as short as 300 fs. The material is a lso highly resistive and promises to be an excellent candidate for opt oelectronic applications requiring short carrier lifetime and high dar k isolation. (C) 1997 American Institute of Physics.