14-GHz GaNAsSb Unitraveling-Carrier 1.3-$\mu\hbox{m}$ Photodetectors Grown by RF Plasma-Assisted Nitrogen Molecular Beam Epitaxy

We report on picosecond pulsed response and 3-dB cutoff frequency of 1.3-μm GaNAsSb unitraveling-carrier photodetectors (PDs) grown by molecular beam epitaxy using a radio-frequency plasma-assisted nitrogen source. The 0.1-mum -thick GaNAsSb photoabsorption layer contains 3.5% of N and 9% of Sb, resulting in a bandgap of 0.88 eV. The dark current densities at 0 and -9 V are 6 and 34 mA/cm
²
, respectively. The GaNAsSb UTC PDs exhibit a temporal response width of 46 ps and a record 3-dB cutoff frequency of 14 GHz at -9 V.