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

Abstract

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.