High-speed photoconductive detectors using GaInAs

Because of its low bandgap, GaInAs lattice matched to InP is a promising material for photodetection for wavelengths to approximately 1.6 μm. In this paper we will present data on high speed photodetectors fabricated using n-type GaInAs grown by molecular beam epitaxy (MBE) on semiinsulating InP substrates. The detectors show high speed response (∼200 ps FWHM) with internal gain of ∼10. From the device characteristics, the electron velocity versus electric field curves in GaInAs are inferred. The high mobility and peak velocity of electrons in GaInAs show a direct relation to the performance of the experimental photoconductive detectors.