Capacitance–Voltage Measurement With Photon Probe to Quantify the Trap Density of States in Amorphous Thin-Film Transistors

We report on a characterization method to quantitatively estimate the interfacial trap density of states (DOS) in thin-film transistors (TFTs): photon-probe capacitance-voltage (CV) measurement. The photo-CV method was compared to photoexcited charge-collection spectroscopy, which is another photon-probe method using current-voltage (I-V) measurement to meet the same purpose. Here, we directly characterized the DOS of amorphous-Si- and amorphous-InGaZnO-based TFTs using the photon-probe CV measurement, and the results turned out to mainly focus the trap DOS at channel/dielectric interface. On the one hand, the DOS profile by photon-probe I-V method appeared to give additional trap information from the transistor back channel.