Single-Scan Monochromatic Photonic Capacitance-Voltage Technique for Extraction of Subgap DOS Over the Bandgap in Amorphous Semiconductor TFTs

We report a novel technique for simultaneous extraction of subgap donor- and acceptor-like density of states [gD(E)andgA(E)] over the subgap energy range(EV<E<EC)using a single-scan monochromatic photonic capacitance-voltage technique in n-channel amorphous indium–gallium–zinc–oxide thin-film transistors. In the proposed technique, we applied two different equivalent circuit models for the photoresponsive carriers excited fromgD(E)andgA(E)under depletion(VGS<VFB)and accumulation(VGS<VFB)bias by employing a sub-bandgap optical source that includes a relation between photon energy(Eₚₕ)and bandgap energy(Eg)as$h{ν}=Eₚₕ