Transparent and Flexible In2O3 Thin Film for Multilevel Nonvolatile Photomemory Programmed by Light

• Published in: ACS applied electronic materials 2019-03, Vol.1 (3), p.437-443
• Main Authors: Abbas, Sohail, Kumar, Mohit, Ban, Dong-Kyun, Yun, Ju-Hyung, Kim, Joondong
• Format: Article
• Language: English
• ISSN: 2637-6113; 2637-6113
• DOI: 10.1021/acsaelm.8b00139

The optically triggered data processing and storage provides an interesting arena for developing sophisticated next-generation smart windows and computation technology. So far, transparent and flexible metal oxides have shown phenomenal optoelectronic applications. In this article, we report a photomemory of In2O3 thin film deposited on glass and PET substrate using a large-scale sputtering system. The electrical characterization of a device under light and dark conditions reveals vast persistent photoconductivity (PPC) at room temperature. The PPC is systematically exploited for multibit data storage by programming with photon pulse, intensity, and source-to-drain voltage. Similarly, a high degree of persistence (>104 s) is achieved to retain optical information. The underlying working mechanism is attributed to the trapping of photogenerated electrons by oxygen vacancies, while corresponding holes freely participate in electrical transport even after light termination. Finally, the energy band diagram is proposed using the In2O3 work function (4.26 eV measured with KPFM) and bandgap. The functional use of a transparent thin film may provide a solution of the complex multilevel programming architecture. This flexible and lightweight device can be applied in smart transparent electronics, including memories, photodetectors, and solar cells.