Highly efficient pGaSb-nGa1−xAlxSb photodiodes

Highly efficient pGaSb-nGa1−xAlxSb photodiodes were fabricated by liquid-phase-epitaxial growth of an undoped p-type GaSb layer, followed by that of an n-type Ga1−xAlxSb layer with a composition at x=0.7 on a p-type (100) GaSb substrate. Spectral photocurrent response of the diodes measured at various bias voltages and room temperature was fairly flat between 1.0 and 1.7 μm. The external quantum efficiency of the photoresponse was 38% at zero bias and 54% at 1 V reverse bias in the vicinity of 1.2 μm.