Improving the sensitivity of a near-infrared nanocomposite photodetector by enhancing trap induced hole injection

Authors

Liang Shen, University of Nebraska-Lincoln
Yanjun Fang, University of Nebraska-LincolnFollow
Qingfeng Dong, University of Nebraska-LincolnFollow
Zhengguo Xiao, University of Nebraska-LincolnFollow
Jinsong Huang, University of Nebraska-LincolnFollow

Date of this Version

2015

Citation

APPLIED PHYSICS LETTERS 106, 023301 (2015)

Comments

Copyright 2015 AIP Publishing LLC.

Abstract

We report the enhancement of the photoconductive gain of nanocomposite near-infrared photodetectors by a zinc oxide nanoparticles (ZnO NPs) rich surface at the nanocomposite/cathode interface. An argon plasma etching process was used to remove polymer at the surface of nanocomposite films, which resulted in a ZnO NPs rich surface. The other way is to spin-coat a thin layer of ZnO NPs onto the nanocomposite layer. The ZnO NPs rich surface, which acts as electron traps to induce secondary hole injection under reverse bias, increased hole injection, and thus the external quantum efficiency by 2–3 times. The darkcurrent declined one order of magnitude simultaneously as a result of etching the top nanocomposite layer. The specific detectivity at 800 nm was increased by 7.4 times to 1.11x10¹⁰ Jones due to the simultaneously suppressed noise and enhanced gain.