In this work, we introduce a molecular-scale charge trap medium for an organic non-volatile memory transistor (ONVMTs). We use two different types of small molecules, 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) and 2,3,6,7,10,11-hexamethoxytriphenylene (HMTP), which have the same triphenylene cores with either hydroxyl or methoxy end groups. The thickness of the small molecule charge trap layer was sophisticatedly controlled using the thermal evaporation method. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) analysis revealed that there were negligible differences in the chemical structures of both small molecules before and after thermal deposition process. The ONVMTs with a 1-nm-thick HHTP charge trap layer showed a large hysteresis window, approximately 20 V, under a double sweep of the gate bias between 40 V and -40 V. The HMTP-based structure showed a negligible memory window, which implied that the hydroxyl groups affected hysteresis. The number of trapped charges on the HHTP charge trap layer was measured to be 4.21 × 1012 cm-2. By varying the thickness of the molecular-scale charge trap medium, it was determined that the most efficient charge trapping thickness of HHTP charge trap layer was approximately 5 nm.
Bibliographical noteFunding Information:
This work was supported by the Korea Institute of Science and Technology (KIST) Institutional Program (Project No. 2Z04420 ) and was partially supported by BK21 Plus Program and Basic Research Laboratory ( 2015042417 ).
© 2015 Elsevier B.V.
- Charge trap layer
- Organic non-volatile memory transistor
- Small molecule
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Materials Chemistry
- Electrical and Electronic Engineering