PbS nanocrystal and poly(3-hexylthiophene) hybrid vertical photodetector using a graphene electrode

Abstract

A highly sensitive near-infrared vertical photodetector was fabricated by our sandwiching a lead sulfide (PbS) nanocrystal and poly(3-hexylthiophene) hybrid channel between a graphene source electrode and a Au drain electrode. The device showed excellent electric and photoresponse characteristics as a result of the strong near-infrared absorption of PbS nanocrystal, the ultrashort channel of the vertical structure, and the adjustable contact barrier. The device showed a high drain-source current density of about −48 mA/cm2, a responsivity of 149 A/W, an effective quantum efficiency of (2.3 × 104)%, a detectivity of 6 × 108 Jones, and a short rise time of about 14 ms under 808 nm illumination. The hybrid vertical photodetector using a graphene electrode opens up new opportunities in optoelectronics.