Surface Ligands-Mediated PbSe Quantum Dots–InGaZnO Hybrid Infrared Phototransistors

This study investigates near-infrared (IR) phototransistors utilizing hybrid systems of indium gallium zinc oxide (IGZO) and PbSe colloidal quantum dots with distinct surface ligands and diameters. Tetrabutylammonium iodine (TBAI)-modified quantum dot film exhibits an insulative property and abundant traps. Under 1064 nm light illumination, the devices with TBAI-modified quantum dots achieve a high photoresponsivity of 2.63 × 104 A/W, a high detectivity of 1.15 × 1014 Jones, and an exceptional photosensitivity exceeding 107 in transient response. In contrast, the mercaptopropionic acid (MPA)-modified quantum dot film shows higher conductivity and fewer traps, resulting in faster relaxation of photon-induced carriers and a rapid response speed of the devices with MPA-modified quantum dots. Additionally, the device with MPA-modified quantum dots exhibits better air stability compared to the TBAI-modified device. The impact of quantum dot size on device performance was explored, revealing that the device based on larger PbSe quantum dots exhibits superior performance under 1550 nm illumination, with the photoresponsivity and detectivity reaching 4.96 × 105 A/W and 2.88 × 1015 Jones, respectively. This research provides valuable insights and suggests promising applications for IGZO-PbSe quantum dot hybrid systems in the development of high-performance near-IR photodetectors with customizable properties.