CdSe/CdS/ZnS 양자점을 이용한 유기 쌍안정 소자에서 ZnS가 나타내는 전기적 특성 및 효과

Abstract

Nonvolatile memory devices based on hybrid organic/inorganic nanocomposites with excellent advantages of power saving, density storage, mechanical flexibility, low cost, and simple fabrication have been extensively researched owing to their potential applications in next-generation electronic and optoelectronic portable devices. Among the several types of nonvolatile memory devices, organic bistable devices (OBDs) have emerged as an outstanding candidate due to their simple solution process, low cost, and fast writing/erasing speed [9-14]. Semiconductor quantum dots (QDs) are small enough to exhibit quantum effects, and they are typically used in light emitting devices, photovoltaic devices, and photodetector devices. Three types of QDs structurally exist as core, core-shell, and core-shell-shell. The QDs actually cause the effects of electron tunneling and the Coulomb interaction among the electrons to help trap the electrons. QDs have been typically used in the carrier trapping sites in nonvolatile memory devices [15-19]. Even though some investigations about the fabrication and the electrical characteristics of the memory devices utilizing QDs have been performed, studies concerning memory devices fabricated utilizing core-shell-shell QDs have not yet been conducted.

This paper reports data for the effect of the ZnS shell layer on the electrical properties of OBDs fabricated utilizing CdSe/CdS/ZnS core/shell/shell QDs embedded in a poly(methylmethacrylate) (PMMA) layer. X-ray photoelectron spectroscopy (XPS) measurements were performed to determine the constituent elements. The current-voltage (I-V) characteristics were performed to investigate the effect of the ZnS shell layer on the electrical properties of OBDs with CdSe/CdS/ZnS core/shell/shell QDs. Retention time measurements were carried out in order to demonstrate the stability of the devices.