High sensitivity 2.5 μm photodiodes with metastable GaInAsSb absorbing layer

Abstract Al 0.35 Ga 0.65 As 0.03 Sb 0.97 ( p + )/Ga 0.74 In 0.26 As 0.23 Sb 0.77 ( p )/GaSb( n + ) photo long-wavelength cutoff of 2.5 μm have been fabricated on GaSb (111)B substrates. The active GaInAsSb layer was grown by liquid phase epitaxy inside the metastable region of the alloy. These devices without any passivation or antireflection coating exhibit a reverse current of 35 mA/cm 2 (at −1 V) and an external quantum efficiency higher than 40% in the wavelength range 1.3–2.3 μm with a peak value of 52% at 2.1 μm.