High-sensitivity hybrid PbSe/ITZO thin film-based phototransistor detecting from 2100 nm to 2500 nm near-infrared illumination

We report that high absorption PbSe colloidal quantum dots (QDs) having a peak absorbance beyond 2100 nm were synthesized and incorporated into InSnZnO (ITZO) channel layer-based thin film transistors (TFTs). It was intended that PbSe QDs with proportionally less photocurrent modulation can be remedied by semiconducting and low off-current ITZO-based TFT configuration. Multiple deposition scheme of PbSe QDs on ITZO metal oxide thin film gave rise to nearly linear increase of film thickness with acceptably uniform and smooth surface (less than 10 nm). Hybrid PbSe/ITZO thin film-based phototransistor exhibited the best performance of near infrared (NIR) detection in terms of response time, sensitivity and detectivity as high as 0.38 s, 3.91 and 4.55 × 107 Jones at room temperature, respectively. This is indebted mainly from the effective diffusion of photogenerated carrier from the PbSe surface to ITZO channel layer as well as from the conduction band alignment between them. Therefore, we believe that our hybrid PbSe/ITZO material platform can be widely used to be in favour of incorporation of solution-processed colloidal light absorbing material into the high-performance metal oxide thin film transistor configuration.