Carrier recombination lifetime in InAs thin films bonded on low-k flexible substrates

We investigated carrier recombination in InAs thin films obtained by epitaxial lift-off and van der Waals bonding on low-k flexible substrates. Photoconductors are fabricated from the InAs thin films bonded on flexible substrates, and also from films grown on GaAs(001) substrates. By irradiation of 1.55-μm-wavelength laser light with intensity modulation, we characterized frequency responses of the InAs photoconductors by S-parameter measurements. From an analysis of the frequency dependence of the S-parameters, we obtained carrier recombination lifetimes, which are long for the InAs thin films bonded on flexible substrates in comparison with those grown on GaAs(001), attributed to the lower dislocation density in the former.