Low-noise Ga0.47In0.53As photoconductive detectors using Fe compensation

Abstract

We demonstrate a low-noise Ga0.47In0.53As photoconductive detector prepared by liquid phase epitaxy using Fe compensation. A carrier concentration as low as 1.8×1013 cm−3 and a Hall mobility as high as 5390 cm2/Vs have been achieved. This has improved the noise current by 3.7 dB but reduced the gain (∼15) by 4.8 dB as compared to a high-mobility undoped detector grown by vapor phase epitaxy. The Fe incorporation has resulted in a factor of 2 improvement in the fall time (∼1.2 ns), which will reduce the amount of equalization required and hence improve the dynamic range of the detector. When tested in a receiver circuit containing a GaAs field-effect transistor front end at 1 Gb/s, the detector (no AR coating) showed a receiver sensitivity of −30.3 dBm at 1.55 μm for a bit error rate of 10−9.