Silicon-on-insulator and SiGe waveguide photodetectors with Ge/Si self-assembled islands

We have investigated near infrared p–i–n waveguide photodetectors with Ge/Si self-assembled islands as optical active region. Two samples with Ge islands grown by high-pressure chemical vapor deposition were studied. The first sample consists of a p–i–n junction with islands embedded in a silicon-on-insulator waveguide. The second sample consists of a p–i–n junction with Ge island layers embedded in a Si0.98Ge0.02 alloy waveguide. The spectral responsivity of the detectors was measured with a broad-band source and with semiconductor laser diodes. At room temperature both samples exhibit similar responsivities at View the MathML source applied bias, with 55 View the MathML source at View the MathML source and 0.15 View the MathML source at View the MathML source for the Si0.98Ge0.02 alloy (silicon-on-insulator) waveguide. The photocurrent results are correlated to the interband absorption and to the photoluminescence of the islands.