Type II GaSb based photodiodes operating in spectral range 1.5-4.8 /spl mu/m at room temperature

The authors present results of research and development of mid-infrared photodiodes based on antimonide solid solutions operating at room temperature in the spectral range of 1.5-4.8 /spl mu/m. A new physical approach to the design of long-wavelength photodiodes is proposed by using type II broken-gap heterostructures grown by liquid-phase epitaxy on GaSb substrates. The choice of sequence of the narrow-gap and wide-gap layers in the GaSb/InGaAsSb/GaInAsSb and GaSb/InGaAsSb/AlGaAsSb heterostructures allows one to vary the band energy diagram and barrier heights on the interface. Electrical and photoelectrical parameters of three kinds of devices were studied. A detectivity of D/sup *//sub /spl lambda//=4.1/spl times/10/sup 8/ cmHz/sup 1/2//W was found at /spl lambda/=4.7 /spl mu/m, T=300 K.