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0997-I01-01

Organic- and Bio-Based Digital Memory Devices Ricky J. Tseng1,2, Liping Ma1, Yan Shao1, and Yang Yang1,3 1 Materials Science & Engineering, UCLA, Los Angeles, CA, 90095 2 FENA center, UCLA, Los Angeles, CA, 90095 3 FENA center, California Nano System Institute, UCLA, Los Angeles, CA, 90095 ABSTRACT Organic memory devices are considered as a viable approach for future information processing. We show our recent progress of organic memory devices evolving from multiple layers structure to solution synthesis hybrid biomolecule structure. By forming a thin organic-nanoparticle layer or virus-nanoparticle layer in the crossbar junction, electronic memory effect based on electrical bistable states with a large on/off ratio, and long retention time is achieved. Temperature dependent data retention shows the nanoparticle formation determines the charge storage activation energy. Such organic, bio-inorganic nanostructures are promising for future memory technology. INTRODUCTION There has been motivation in searching of advanced materials for data storage in the development of future information technology, since the limitation of scaling problem of semiconductor industry will face in the near future. Many methods have been reported for inorganic nonvolatile memory, such as electrical switching in oxide semiconductors [1], phase change memory [2], and programmable metallization cell [3]. Alternatively, organic materials are promising candidates for new memory technology because the self assembly provides the device size down to nanoscale dimension. Using the organic materials not only can simplify the manufacturing process, but also take advantages of low cost, flexible, and light weight. The key point to create the memory effect is processed through charge storage sites which can be created either on nanoparticles [4], on redox molecules [5], or between interfaces of donor/acceptor molecules [6] and organic/nanoparticles [7]. The charge storage state, i.e. memory state, undergoes a charge transfer process for example from molecule to nanoparticle or molecule to molecule. After the charge transfer, the trapped charges are thus stable due to the physical barrier [8]. EXPERIMENT There are two types of device structures investigated in this report. The first one is the layered organic/organic-metal cluster/organic structure [9] as shown in Figure 1(a). The organic layer utilize 2-amino-4,5-imidazoledicarbonitrile (AIDCN). The middle mixture layer is done by co-evaporation of 1:1 ratio AIDCN and Al nanoparticles. The top and bottom electrodes are Al. These layers are deposited sequentially in a chamber with vacuum of 5◊10-6 torr. The thicknesses of AIDCN and mixture layer are 50 nm and 20 nm, respectively. Figure 1(b) shows the other device structure for tobacco mosaic virus-platinum nanoparticles (TMV-Pt) conjugate system, which is using a nanocomposite layer sandwiched between two electrodes. The

nanocomposite layer is approached by spin coating with a solution of ~0.1 wt% TMV-Pt nanowires in a 1.2 wt% polyvinyl a