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

Abstract: We report color-selective photodetection from intermediate, monolayered, quantum dots (QDs) buried in between amorphous-oxide semiconductors. The proposed active channel in phototransistors is a hybrid configuration of oxide-QD-oxide (OQO) layers, where the gate-tunable electrical property of the silicon-doped, indium-zinc-oxide (SIZO) layers is incorporated with the QD color-selective optical property. A record-high detectivity (8.1*10^13 Jones) is obtained, along with three major findings: fast charge separation in QD monolayers; efficient charge transport through high-mobility SIZO 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 QDs in the OQO configuration. These results facilitate the realization of red-green-blue (RGB), color-selective detection exhibiting a photoconductive gain of 107, obtained using a room-temperature deposition of SIZO layers and a QD-solution process. This work offers promising opportunities in emerging applications for color detection with sensitivity, transparency, and flexibility.