Color-selective photodetection from intermediate colloidal quantum dots buried in amorphous-oxide semiconductors

We report color-selective photodetection from intermediate, monolayered, quantum dots buried in between amorphous-oxide semiconductors. The proposed active channel in phototransistors is a hybrid configuration of oxide-quantum dot-oxide layers, where the gate-tunable electrical property of silicon-doped, indium-zinc-oxide layers is incorporated with the color-selective properties of quantum dots. A remarkably high detectivity (8.1 × 10¹³ Jones) is obtained, along with three major findings: fast charge separation in monolayered quantum dots; efficient charge transport through high-mobility oxide layers (20 cm² V^-1 s^-1); and gate-tunable drain-current modulation. Particularly, the fast charge separation rate of 3.3 ns^-1 measured with time-resolved photoluminescence is attributed to the intermediate quantum dots buried in oxide layers. These results facilitate the realization of efficient color-selective detection exhibiting a photoconductive gain of 10⁷, obtained using a room-temperature deposition of oxide layers and a solution process of quantum dots. This work offers promising opportunities in emerging applications for color detection with sensitivity, transparency, and flexibility.