5-THZ BANDWIDTH FROM A GAAS-ON-SILICON PHOTOCONDUCTIVE RECEIVER

We demonstrate that GaAs grown by molecular beam epitaxy on silicon ha s ideal characteristics for THz receiver applications. The lattice mis match between silicon and GaAs causes a disordered growth of GaAs, red ucing the carrier lifetime to 1.8 ps. This is similar to the character istics observed in low temperature grown GaAs. Furthermore, the high r esistivity silicon substrate has a very low absorption and dispersion in the far infrared. This makes it an ideal material in THz system app lications, and we show that a maximum frequency of 5 THz and a sixfold increase in sensitivity can be obtained using a GaAs-on-silicon based THz detector.