Nanowire-based fi eld-effect transistors (FETs) and diodes have been continuously studied along with a great variety of semiconductor nanowires (NWs), including Si, Ge, SiGe, GaN, InP, and ZnO. [1][2][3][4][5][6][7][8] Among all the NW materials, ZnO appears to have relatively good metal electrode-semiconductor contact, which improves the device fabrication yield. [7][8][9][10][11][12][13][14][15][16][17] Therefore, using a long ZnO NW it may be possible to realize one-dimensional (1D) NW electronics, which may contain a FET, [ 7 , 10-14 ] diode, [ 8 , 14,15 ] resistor, memory, [ 16 , 17 ] and other components in a single NW, even though such 1D electronics have rarely been demonstrated so far. [ 8 , 13,14 ] Since nonvolatile memory is an important component for device electronics in general, quite a few studies on memory components in NW dimensions have been reported. However, most attempts were property characterization studies of nanomaterials and prototype devices in general, [16][17][18][19][20][21][22][23][24][25][26] and indeed substantial efforts to incorporate the memory devices into 1D circuit electronics are diffi cult to fi nd. [ 27 ] In particular, ferroelectric memory NW FETs [ 16 , 21 , 22 ] are very rare while charge injection memory-type devices [ 17-20 , 27 ] are relatively common. In the work reported here, we have fabricated a top-gate ferroelectric memory FET from a ZnO NW and the organic copolymer poly(vinylidenefl uoride-trifl uoroethylene) [P(VDF-TrFE)], aiming at a 1D nonvolatile memory circuit in NW-based electronics. Since our single ZnO NW was long enough to have an extra region for an electrical resistor beyond the main region for the top-gate ferroelectric FET (FeFET) channel, we were able to simply realize a ferroelectric memory inverter circuit using one single NW. Our success is closely related to how we patterned the top-gate metal on the organic ferroelectric polymer, which was not easy to perform by photolithography for a channel just a few micrometers long contacting P(VDF-TrFE). Our FeFET with 150 nm-thin ZnO NW channel clearly displayed a memory hysteresis window, which is as large as ca. 20 V, along with an average linear mobility of ca. 67 cm 2 V − 1 s − 1 . This memory window was confi rmed in voltage hysteresis characteristics (VHCs) of our memory circuit, which consists of the ZnO NW-based FeFET and serially connected NW www.advmat.de www.MaterialsViews.com wileyonlinelibrary.com

For the first time, we demonstrated photostable and dynamic rectification in ZnO nanowire (NW) Schottky diode circuits where two diodes are face-to-face connected in the same ZnO wire. With their properties improved by H-doping from atomic layer deposited Al(2)O(3) passivation, our ZnO NW diode circuits stably operated at a maximum frequency of 100 Hz displaying a good rectification even under the lights. We thus conclude that our results promisingly appoached one-dimensional nanoelectronics.

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We demonstrate logic and static random access memory (SRAM) circuits using a 100 μm long and 100 nm thin single ZnO nanowire (NW), which acts as a channel of field-effect transistors (FETs) with Al2O3 dielectrics. NW FETs are thus arrayed in one dimension to consist of NOT, NAND, and NOR gate logic, and SRAM circuits. Two respective top-gate NW FETs with Au and indium-tin-oxide (ITO) were connected to form an inverter, the basic NOT gate component, since the former gate leads to an enhanced mode FET while the latter to depletion mode due to their work function difference. Our inverters showed a high voltage gain of 22 under a 5 V operational voltage, resulting in successful operation of all other devices. We thus conclude that our long single NW approach is quite promising to extend the field of nano-electronics.

We report on a ZnO-based logic inverter utilizing two field effect transistors (FETs), whose respective channel has different wire-diameters under a top-gate dielectric of poly-4-vinylphenol. One FET with nanowire (160 nm) channel displayed an abrupt drain current (ID) increase and fast ID saturation near its positive threshold voltage (Vth) while the other FET with mesowire (770 nm) showed a thin-film transistor-like behavior and a negative Vth. When the nanowire and mesowire FETs were, respectively, used as a driver and a load, our inverter demonstrated an excellent voltage gain as high as 25 under a supply voltage of 20 V.