Mid Wavelength Type II InAs/GaSb Superlattice Avalanche Photodiode With AlAsSb Multiplication Layer

We report on a mid wavelength avalanche photodiode (APD) device with a separate absorption and multiplication structure. Type II InAs/GaSb superlattices are used as the absorber and lattice-matched high bandgap AlAsSb material is used as the multiplication layer. A reference
p-i-n
device that has the same absorption layer as that of the APD is also fabricated for comparison. Significant gain is observed for the APD. The 50% cutoff wavelength of the APD is
$3.15~\mu \text{m}$
at 77 K. Compared to the
p-i-n
device, at 77 K, the APD’s the multiplication gain reaches 32.1 and the corresponding responsivity is 7.07 A/W for the peak wavelength of
$2.51~\mu \text{m}$
when the reverse bias voltage is 29.4 V. When temperature is changed to 100, 150 and 200 K, the gain becomes 28.1, 15.9 and 6.1, respectively.