Enhanced photocurrent in organic photodetectors by the tunneling effect of a hafnium oxide thin film as an electron blocking layer

Chan Hyuk Ji; Ji Young Lee; Kee Tae Kim; Se Young Oh

doi:10.1039/c9ra06230k

Enhanced photocurrent in organic photodetectors by the tunneling effect of a hafnium oxide thin film as an electron blocking layer

RSC Adv. 2019 Sep 23;9(51):29993-29997. doi: 10.1039/c9ra06230k. eCollection 2019 Sep 18.

Authors

Chan Hyuk Ji¹, Ji Young Lee¹, Kee Tae Kim¹, Se Young Oh¹

Affiliation

¹ Dept. of Chemical and Biomolecular Engineering, Sogang University Seoul 04107 Republic of Korea syoh@sogang.ac.kr.

Abstract

To achieve high detectivity of organic photodetectors (OPDs), we investigated hafnium oxide (HfO₂) as an electron blocking layer in an attempt to obtain a low leakage current and high photocurrent by the tunneling effect. The prepared devices consisted of indium tin oxide (ITO)/HfO₂/(poly(3-hexylthiophene-2,5-diyl)[P3HT]:PC₆₀BM)/Yb/Al. To explore the tunneling effect in a hafnium oxide thin film, we fabricated a thin film using successive ionic layer deposition. The results for hafnium oxide were compared with those for aluminum oxide and poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate) (PEDOT:PSS). We found that hafnium oxide results in a low leakage current and high photocurrent owing to the tunneling effect in the OPDs. The resulting detectivity of 1.76 × 10¹² Jones for a film thickness of 5.5 nm and bandwidth of ∼100 kHz is suitable for commercialization.