title: Multifunctional organic phototransistor-based nonvolatile memory achieved by UV/ozone treatment of the Ta₂O₅ gate dielectric.
abstract: An organic phototransistor (OPT) shows nonvolatile memory effect due to its novel optical writing and electrical erasing processes. In this work, we utilize an organic light-emitting diode (OLED) as the light source to investigate OPT-based memory (OPTM) performance. It is found that the OPTM can be used as either flash memory or write-once read-many-times memory by adjusting the properties of the Ta2O5 gate dielectric layer. UV/ozone treatment is applied to effectively change dielectric properties of the Ta2O5 film. The mechanisms for this are examined by X-ray photoelectron spectroscopy and capacitance-voltage measurement. It turns out that the densities of oxygen vacancies and defects in the first 1.8 nm Ta2O5 films near the Ta2O5/semiconductor interface are reduced. Furthermore, for the first time, we use this multifunctional OPTM, which unites the photosensitive and memory properties in one single device, as an optical feedback system to tune the brightness of the OLED. Our study suggests that these OPTMs have potential applications in tuning the brightness uniformity, improving the display quality and prolonging the lifetime of flat panel displays.
authors.affiliation: Key Laboratory of Organic Optoelectronics & Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University , Beijing 100084, China.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Liu
authors.forename: Haoyan
authors.initials: H
authors.lastname: Zhao
authors.forename: Guifang
authors.initials: G
authors.lastname: Dong
authors.forename: Lian
authors.initials: L
authors.lastname: Duan
authors.forename: Dong
authors.initials: D
authors.lastname: Li
authors.forename: Liduo
authors.initials: L
authors.lastname: Wang
authors.forename: Yong
authors.initials: Y
authors.lastname: Qiu