Amorphous indium-gallium-zinc-oxide as electron transport layer in organic photodetectors

• Published in: Applied physics letters 2015-04, Vol.106 (14)
• Main Authors: Arora, H., Malinowski, P. E., Chasin, A., Cheyns, D., Steudel, S., Schols, S., Heremans, P.
• Format: Article
• Language: English
• Subjects: Applied physics; Backplanes; Bias; Buffer layers; BUTYRIC ACID; COMPARATIVE EVALUATIONS; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Dark current; ELECTRIC CURRENTS; ELECTRIC POTENTIAL; Electron transport; ELECTRONS; ESTERS; FABRICATION; Gallium; GALLIUM COMPOUNDS; Indium; INDIUM COMPOUNDS; Indium gallium zinc oxide; LAYERS; PHOTODETECTORS; Photodiodes; Photometers; READOUT SYSTEMS; Reproducibility; State of the art; TITANIUM OXIDES; VISIBLE SPECTRA; Visible spectrum; ZINC OXIDES
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4917235

Amorphous indium-gallium-zinc-oxide (a-IGZO) is demonstrated as an electron transport layer (ETL) in a high-performance organic photodetector (OPD). Dark current in the range of 10 nA/cm2 at a bias voltage of −2 V and a high photoresponse in the visible spectrum were obtained in inverted OPDs with poly(3-hexylthiophene) and phenyl-C61-butyric acid methyl ester active layer. The best results were obtained for the optimum a-IGZO thickness of 7.5 nm with specific detectivity of 3 × 1012 Jones at the wavelength of 550 nm. The performance of the best OPD devices using a-IGZO was shown to be comparable to state-of-the-art devices based on TiOx as ETL, with higher rectification achieved in reverse bias. Yield and reproducibility were also enhanced with a-IGZO, facilitating fabrication of large area OPDs. Furthermore, easier integration with IGZO-based readout backplanes can be envisioned, where the channel material can be used as photodiode buffer layer after additional treatment.