>30 G Omega isolation of GaAs devices on doped Si via undoped buffer layers-application to symmetric self-electrooptic effect devices

The authors demonstrate that by using undoped GaAs buffer layers, high-quality GaAs devices (in this case, surface-normal reflection modulator/detectors) may be grown on doped silicon substrates with >30-G Omega isolation. The resistivity of the buffer layers is estimated to be >2.4*10/sup 7/ Omega -cm. Isolation is demonstrated by forming a symmetric self-electrooptic effect device of two of the modulators. Bistable contrasts of 2.9:1 and 1.8:1 are obtained with 7-V and 2-V supply biases, respectively.<>