The AgTCNQ thin-film was prepared by vacuum vapor co-deposition and characterized by infrared spectral analysis,and then a uniform AgTCNQ （TCNQ-- 7,7,8,8-tetracyanoquinodimethane） thin-film layer was sandwiched in a Ti/AgTCNQ/Ati crossbar structure array as organic bistable devices （OBD）.A reversible and reproducible memory switching property,caused by intermolecular charge transfer （CT） in the AgTCNQ thin-film, was observed in the organic bista- ble devices. The positive threshold voltage from the high impedance state to the low impedance was about 3.8-5V, with the reverse phenomenon occurring at a negative voltage of - 3.5- - 4. 4V,lower than that with a CuTCNQ active layer. The crossbar array of OBDs with AgTCNQ is promising for nonvolatile organic memory applications.
A one-time programmable metal-molecule-metal device, with a modified Rotaxane LB film as the functional layer, is proposed for potential use in organic programmable and fault tolerant circuits like inorganic anti-fuse devices used in field programmable gate arrays. All fabrication methods involved are low temperature processes, ensuring that this device can be integrated with other organic devices. Electrical measurements show that this device has a good one-time programming capability. Its break down voltage is 2.2V, off-state resistance is 15kΩ, and on-state resistance is 54Ω These characteristics come from the penetration of metal atoms into molecular film under high electronic field.
This paper proposes an effective method of fabricating top contact organic field effect transistors by using a pho- tolithographic process. The semiconductor layer is protected by a passivation layer. Through photolithographic and etching processes, parts of the passivation layer are etched off to form source/drain electrode patterns. Combined with conventional evaporation and lift-off techniques, organic field effect transistors with a top contact are fabricated suc- cessfully, whose properties are comparable to those prepared with the shadow mask method and one order of magnitude higher than the bottom contact devices fabricated by using a photolithographic process.
Among the many possible device configurations for organic memory devices,organic field-effect transistor (OFET) memory is an emerging technology with the potential to realize lightweight,low-cost,flexible charge storage media.In this feature article,the recent progress in the classes of OFET-based memory,including floating gate OFET memory,polymer electret OFET memory,ferroelectric OFET memory and several other kinds of OFET memories with unique configurations,are introduced.Finally,the prospects and problems of OFETs memory are discussed.
WANG HongPENG YingQuanJI ZhuoYuLIU MingSHANG LiWeiLIU XingHua
In the case of N-type solar cells,the anti-reflection property,as one of the important factors to further improve the energy-conversion efficiency,has been optimized using a stacked Al_2O_3/SiN_x layer.The effect of SiN_x layer thickness on the surface reflection property was systematically studied in terms of both experimental and theoretical measurement.In the stacked Al_2O_3/SiN_x layers,results demonstrated that the surface reflection property can be effectively optimized by adding a SiN_x layer,leading to the improvement in the final photovoltaic characteristic of the N-type solar cells.
Organic field-effect transistors (OFETs) have received significant research interest because of their promising applications in low cast, lager area, plastic circuits, and tremendous progress has been made in materials, device performance, OFETs based circuits in recent years. In this article we introduce the advances in organic semiconductor materials, OFETs based integrating techniques, and in particular highlight the recent progress. Finally, the prospects and problems of OFETs are discussed.
WANG HongJI ZhuoYuLIU MingSHANG LiWeiLIU GeLIU XingHuaLIU JiangPENG YingQuan
This paper reports a procedure of soft x-ray lithography for the fabrication of an organic crossbar structure. Electron beam lithography is employed to fabricate the mask for soft x-ray lithography, with direct writing technology to the lithograph positive resist and polymethyl methacrylate on the polyimide film. Then Au is electroplated on the polyimide film. Hard contact mode exposure is used in x-ray lithography to transfer the graph from the mask to the wafer. The 256-bits organic memory is achieved with the critical dimension of 250 nm.
