Solution-Processed Ag-TiO2 Nanostructure-Based Schottky Junction Thin Films for Narrowband Hot-Electron Photodetectors

It is not very easy to capture hot plasmonic electronsfor photodetectionin a photodetector. In this work, an in situ grown Ag-TiO2 nano-Schottky junction thin film that contains a highly dense silver(Ag) nanoparticle (NP) surrounded by TiO2 is depositedby a solution-processed technique. This Ag-TiO2 nano-Schottkyjunction has a low barrier height and a high interface area with theleast interface state, which enables efficient hot-electron transferto the conduction band of TiO2, which is realized in theexternal quantum efficiency (EQE) data. This EQE data show intensephotocurrent formation in the region of plasmonic absorption of AgNP, indicating the primary contribution of hot electrons on photocurrentproduction. As a consequence, a narrowband photodetector with fullwidth at half-maximum (FWHM) of & SIM;55 nm is fabricated by utilizingthis Ag-TiO2 nano-Schottky junction thin film. Moreover,due to the high density of the Ag NP, the photodetector shows gooddetectivity in combination with fast response time. This photodetectoris fabricated on a glass substrate in a photoconductor geometry thatshows a peak detectivity of 3.19 x 10(11) Jones at 420nm with a response time of & SIM;2 s.