High-Speed InSb Photodetectors on GaAs for

Abstract—We report p-i-n type InSb-based high-speed photode-tectors grown on GaAs substrate. Electrical and optical properties of photodetectors with active areas ranging from 7.06 10 6 cm2 to 2.25 10 4 cm2 measured at 77 K and room temperature. Detectors had high zero-bias differential resistances, and the differential resistance area product was 4.5 cm2. At 77 K, spectral measurements yielded high responsivity between 3 and 5 m with the cutoff wavelength of 5.33 m. The maximum responsivity for 80- m diameter detectors was 1.00 105 V/W at 4.35 m while the detectivity was 3.41 109 cm Hz1 2 W. High-speed measurements were done at room temperature. An optical parametric oscillator was used to generate picosecond full-width at half-maximum pulses at 2.5 m with the pump at 780 nm. 30- m diameter photodetectors yielded 3-dB bandwidth of 8.5 GHz at 2.5 V bias. Index Terms—High-speed, infrared, photodetector