High detectivity AlInSb mid-infrared photodiode sensors with dislocation filter layers for gas sensing application

High detectivity AlInSb mid-infrared photodiode sensor was fabricated on GaAs substrate. By inserting two pairs of 20 nm dislocation filter layers with high Al composition into n-type buffer layer, threading dislocation density was reduced to 1/3 or less. Resulting photodiode sensor showed high resistivity-area product (RA) of
$19\ \mathrm{M}\Omega\mu \mathrm{m}^{2}$
and high normal-incidence detectivity of
$1.7\times 10^{9}\ \mathrm{cm}\ \surd \mathrm{Hz}/\mathrm{W}$
at
$3.3\ \mu \mathrm{m}$
at room temperature. To the best of our knowledge, this photodiode shows the highest performance in highly mismatched alloy system, i.e. AlInSb on GaAs substrate.