Annealing Effect\non the Performance of PbS Quantum\nDot Sensitized a‑IGZO Transistors for Photodetection Application

PbS quantum dots have demonstrated potential as cost-effective\nmaterials for near-infrared photodetectors. Nevertheless, the performance\nof single-layer PbS quantum dot photodetectors remains unsatisfactory\ndue to the low carrier mobility and high defect state concentration\nof colloidal quantum dot thin films. In this article, PbS quantum\ndot films are employed as the sensitizing layers for a-IGZO-based\nfield-effect transistors (FET), which are able to achieve a low dark\ncurrent and relatively high photocurrent simultaneously when working\nin the Poole–Frenkel emission region. The as prepared device\nshows a high responsivity of 25.89 A/W and detectivity of 2.46 ×\n10<sup>12</sup> Jones, but very slow response speed with a decay time\nof 554 ms, which should be attributed to the high trap density in\nthe PbS quantum dots film. Thus, we proposed a rapid annealing oxidation\nprocess to passivate the defects. As a result, after annealing in\nair at 100 °C for 10 min, the response speed of the device is\nsignificantly improved, and the decay time is as short as 2.5 ms,\nonly at the expense of some responsivity and selectivity loss. However,\nfurther increasing the annealing temperature leads to excessive photocurrent\nloss and even affects the response speed improvement.