Enhanced performance and stability in InGaZnO NIR phototransistors with alumina-infilled quantum dot solid

The optimized ALD infilling process for depositing Al₂O₃ in the vertical direction of PbS QDs enhances the photoresponsivity, relaxation rate and the air stability of PbS QDs hybrid IGZO NIR phototransistors. Infilled Al₂O₃, which is gradually deposited from the top of PbS QDs to the PbS/IGZO interface (1) passivates the trap sites up to the interface of PbS/IGZO without disturbing charge transfer and (2) prevents QDs deterioration caused by outside air. Therefore, an Al₂O₃ infilled PbS QD/IGZO hybrid phototransistor (AI-PTs) exhibited enhanced photoresponsivity from 96.4 A/W to 1.65 × 10² A/W and a relaxation time decrease from 0.52 to 0.03 s under NIR light (880 nm) compared to hybrid phototransistors without Al₂O₃ (RF-PTs). In addition, AI-PTs also showed improved shelf stability over 4 months compared to RF-PTs. Finally, all devices we manufactured have the potential to be manufactured in an array, and this ALD technique is a means of fabricating robust QDs/metal oxide hybrids for optoelectronic devices.