550 GHz bandwidth photodetector on low-temperaturegrown molecular-beamepitaxial GaAs

Abstract
The authors demonstrate that a 550 GHz bandwidth photodetector can be fabricated on low-temperature grown MBE GaAs. The pulse response shows 0.4 and 0.6 ps rise and fall times, respectively. The bandwidth is in agreement with a value calculated using a carrier lifetime of 0.2 ps, measured by femtosecond time-resolved reflectivity, and a capacitance of 0.014 fF/µm2, determined from microwave measurements. The device bandwidth is RC limited.