Inorganic ZnTe Hole Transport Layer for PbS Quantum Dot Infrared Photodetectors and Imagers

Abstract

Abstract PbS quantum dot (QD) photodetectors promise a new generation of short‐wave infrared detection technology due to their low cost and ease of integration. The organic ligand‐capped hole transport layers (HTLs) suffer from poor film quality, limiting potential applications in large focal plane arrays. Herein, a robust inorganic HTL – one based on sputtered ZnTe – is reported that is compatible with microelectronic fabrication. The significance of a mild post‐annealing process in band alignment and interface passivation is identified. A surface dipole mechanism is proposed – based on the first‐principles calculations – to explain the upward shift in the energy band of ZnTe. The resultant PbS QD photodetectors based on ZnTe HTL shows a specific detectivity of 1.32 × 10 12 Jones at ≈1300 nm, nearly one order of magnitude higher than that of the control devices. PbS QD imager with a pixel array of 640 × 512 is finally fabricated, verifying the compatibility of the ZnTe HTL with silicon‐based readout circuitry.