Investigation of persistent photoconductance and related electron mobility in thin IGZO layers with the PDL Hall technique

A chemically treated IGZO-based highly visible-blind UV phototransistor with suppression of the persistent photoconductivity effect

“…Consequently, the presence of two free carriers originating from the shallow donor-like states near the CBM under illumination of all wavelengths promotes a significant negative shift of V th . 67 On the other hand, as shown in Fig. 4(b)-(e), it is evident that no photoresponse or a slight positive change in V th was observed as the 2EEG-IGZO was exposed to red light (l = 635 nm) and green light (l = 520 nm) under the same conditions.…”

“…Furthermore, the phototransistor showed a substantial amount of photocurrent under UV illumination, which was facilitated by the presence of two free carriers originating from the shallow donor-like states near the CBM. 67 This phenomenon resulted in a negative shift in V th under illumination. Since semiconductors efficiently absorb photons when the incident radiation has higher energies than the material's bandgap, 37 the photocurrent, even under lower photon energies of visible light than the IGZO bandgap, is trap-assisted photocurrent induced by a large amount of defect sites in the bandgap of IGZO.…”