• Vilkman, Marja
• Laiho, Ari
• Sandberg, Henrik G. O.
• Baral, Jayanta
• Tenhu, Heikki
• Hassinen, Tomi
• Ikkala, Olli
• Ras, Robin
• Österbacka, Ronald
• Nuopponen, Markus

Abstract

Future organic electronic and nanoelectronic applications will needorganic memories as the devices and circuits get more complex. However, untilvery recently there has been limited research on the subject. Recentdiscoveries allow organic bistable devices to be used for nonvolatile memoryapplications [1]. We present a memory device concept that utilizes metallicnanoparticles dispersed in an insulating matrix. The simple structure allowsone-step active layer deposition and thus paves the way for roll-to-rollprocessing.The main objective of this work is to develop memory units that can bemanufactured in a rapid and economical fashion. The printing process offerstools for this purpose, but requires air-stable materials. Thus the use ofgold nanoparticles (Figure 1) in a polystyrene matrix is a feasiblealternative. However, other materials are also investigated.Figure 1: Gold nanoparticle with polystyrene tails (left) and a TEM picture,which shows that the particles are evenly distributed in the polymer matrix(right).Even distribution of nanoparticles is a requirement for optimal deviceoperation. The TEM picture in Figure 1 shows that the gold particles spreadevenly in the matrix. A resistance switching phenomenon can be observed inthis nanoscale composite when contacted in a sandwich structure. Although theswitching is still inconsistent, the negative differential resistance isconsistent, which can also be utilized in a memory device. (Figure 2)Figure 2: I-V characteristics of a Au-particle memory device.1. Himadri S. Majumdar, Jayanta K. Baral, Ronald Österbacka, Olli Ikkala, andHenrik Stubb, Fullerene-based bistable devices and associatednegative-differential-resistance effect, Organic Electronics 6 (2005) 188-192.

Topics

• nanoparticle
• Deposition
• impedance spectroscopy
• polymer
• gold
• composite
• transmission electron microscopy