Beryllium compensation doped InGaAs/GaAsSb superlattice photodiodes

In this paper, the authors reported recent work on the growth and fabrication of InGaAs/GaAsSb type II superlattice detectors by solid source molecular beam epitaxy. Superlattice materials with different Beryllium (Be) doping concentration were grown and characterized by high resolution X-ray diffraction, Hall Effect technique, and photoluminescence. The results showed that doping concentration of the superlattice was sensitive to the Be temperature. A p-π-n InGaAs/GaAsSb T2SL photodiode was grown on an InP substrate. The full width at half maximum of the first order satellite peak from X-ray diffraction was 36 arcsec. The photodiode with 7 nm InGaAs and 5 nm GaAsSb in each period showed a 50% cutoff wavelength of 2.35 μm at 293 K. The dark current density at −50 mV bias was 0.54 mA/cm2 and the resistance-area product at zero bias (R0A) was 46 Ω ⋅ cm2. The peak detectivity was 4.4 × 1010 cm Hz1/2/W. The quantum efficiency at 2.1 μm was measured to be 48.2%.