Nonlinear behaviors of low-temperature-grown GaAs-based photodetectors around 1.3-/spl mu/m telecommunication wavelength

We observed distinct bandwidth degradation behaviors in low-temperature-grown GaAs (LTG-GaAs)-based traveling-wave photodetectors (PDs) under /spl sim/1300-nm telecommunication wavelength operation. Compared with the bandwidth degradation behaviors of different excitation wavelengths (/spl sim/800 and /spl sim/1550 nm) in LTG-GaAs-based PDs, the saturation behaviors at the studied wavelength are more serious and can be attributed to "hot electron" effect of photogenerated carriers. The disclosed unique material properties of LTG-GaAs are important for its applications in ultrafast optoelectronics and understanding its carrier dynamics with the defect states.