Device performance enhancement via a Si-rich silicon oxynitride buffer layer for the organic photodetecting device

An advanced organic photodetector (OPD) with a butter layer of Si-rich silicon oxynitride (SiO_xN_y) was fabricated. The detector structure is as follows: Indium tin oxide (ITO) coated glass substrate/SiO_xN_y(10 nm)/naphthalene-based donor:C60(1:1)/ITO. Values of x and y in SiO_xN_y were carefully controlled and the detector performances such as dark current and thermal stability were investigated. When the values of x and y are 0.16 and 0.66, the detector illustrates low dark current as well as excellent thermal stability. In the OPD, silicon oxynitride layer works as electron barrier under reverse bias, leading to the decrease of dark current and increase of detectivity. Since the band gap of silicon oxynitride unlike conventional buffer layers can also be controlled by adjusting x and y values, it can be adapted into various photodiode applications.