A novel heterostructure interdigital photodetector (HIP) with picosecond optical response

The demonstration of a novel and simple heterostructure interdigital photodetector (HIP) is reported. The detector displays 50- 60 ps symmetric rise and fall times, low operating voltages (∼10-25V), with a dc responsivity greater than 0.3 A/W at λ = 0.83 µm. The results obtained are comparable to the fastest commercial high speed detectors available today. The device is compatible with planar technology and thus should lend itself to integration with MESFET´s or other microwave integrated circuits. Lastly, the concept of using a heterostructure to confine the injected carriers should ultimately provide high speed operation by limiting the detrimental effects of carrier diffusion and traps in the semi-insulating substrate.