Effect of the ZnS shell layer on the charge storage capabilities of organic bistable memory devices fabricated utilizing CuInS2-ZnS core-shell quantum dots embedded in a poly(methylmethacrylate) layer

The electrical characteristics of organic bistable memory devices (OBDs) fabricated utilizing CuInS2 (CIS) core or CIS-ZnS core-shell quantum dots (QDs) embedded in a poly(methylmethacrylate) (PMMA) layer on indium-tin-oxide (ITO) coated glass substrates were investigated. X-ray photoelectron spectroscopy spectra demonstrated that the stoichiometries of the QDs embedded in a PMMA layer were CIS or CIS-ZnS QDs. Current-voltage measurements on Al/CIS or CIS-ZnS QDs embedded in PMMA layer/ITO glass devices at 300 K showed current bistabilities. The maximum ON/OFF current ratios of the OBDs with CIS or CIS-ZnS QDs were approximately 1 x 10(3) and 1 x 10(5), respectively. The retention number of ON and OFF states was measured by 1 x 10(5). The memory mechanisms of the OBDs with CIS or CIS-ZnS QDs are described on the basis of the experimental results. (C) 2013 Elsevier B. V. All rights reserved.This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2011-0025491)