Extraction of Subgap Donor States in a-IGZO TFTs by Generation–Recombination Current Spectroscopy

A physics-based generation-recombination current (JG r) spectroscopy is proposed for the extraction of the sub gap donorlike density of states (DOS) of amorphous InGaZnO thin-film transistors. Physics-based Shockley-Read-Hall recombination through the subgap DOS over the bandgap is fully considered, and the potential for the carrier concentration is calculated through the DeAOTS model. The extracted parameters for the exponential deep donorlike states are NDD= 5.5 × 1021[cm-3· eV-1] and kTDD= 0.115 [eV].