Modulation-doped Ga0.47In0.53As/Al0.48In0.52As planar photoconductive detectors for 1.0–1.55-μm applications

We demonstrate a Ga0.47In0.53As/Al0.48In0.52As modulation-doped photoconductive detector. The detector has a built-in electric field to separate photogenerated electron-hole pairs. This allows the electron lifetime to be precisely determined by electrode spacings. When tested by a 200-ps, λ=1.3 μm laser pulse, the detector shows an internal gain of 18, a peak external quantum efficiency of 300%, a rise time of 80 ps, a full width at half-maximum of 250 ps, and an internal gain-bandwidth product of 72 GHz. Typical devices have 4-μm spacings between electrodes and 94-μm widths. The detector has a spectral response between 0.6 and 1.65 μm with a dip at 0.86 μm. We also measured the noise power of the detector at room temperature. With its capability to be integrated with a modulation-doped field-effect transistor, this detector can be useful in a monolithic integrated photoreceiver.