Study On Mechanical And Electrical Properties Of The PbS Micro/Nanowires

At present, it is reaching the physical critical point of the existing materials and technologies in the semiconductor field, and new technology breakthroughs in semiconductor materials are impending. Developing micro/nanoscale metalsemiconductor-metal(MSM) system for nonvolatile random access memory(NRAM) is one key technological step that has attracted increasing attention in recent years.PbS is an important semiconductor material. Owing to a band gap of 0.41 eV and a large exciton Bohr radius of 18 nm, it has many eminent optical and electrical properties, and has a wide application in nonlinear optical devices, IR detectors and display devices. Here, we used PbS micro/nanowire to the preparation of resistance random access memory(RRAM) and piezoresistance random access memory(PRRAM). And their resistive switching(RS) and memory properties were researched in detail.The two-terminal devices, based on an individual PbS micro/nanowire with Ag electrodes, were constructed on a flexible insulating plastic substrate. And the affect of annealing at the ends of device to RS and RRAM had been studied. For the unannealed device, it can be obviously seen that the device exhibits a symmetrical RS characteristic. And the I-V curves show relatively large hysteresis loops, indicating the nonvolatile data storage capability. For the device annealed at one end, it exhibits typical bipolar RS properties. When the unannealed electrode is subject to relatively low negative bias, the device is almost nonconductive. With increasing negative bias, however, the output current of the device increases abruptly with a threshold voltage of around 0.3-0.8 V. For the device annealed at both ends, an analog type RS effect has been discovered. Its I-V curves show relatively small hysteretic properties, indicating a poor nonvolatile data storage capability. Moreover, the piezoresistance switching effect and PRRAM properties of device had also been researched, When the device is loaded a compressive strain of-0.26%, its resistance will decrease from 17 M? to18 K?. Therefore, it can acquire a high off/on ratio of resistance about 944 and a gauge factor(GF) of about 3.6×105.However, when the device is loaded a tensile strain of 0.26%, its resistance increases from 73 k? to 97 M?. And it has a off/on ratio of resistance about 1328 and a gauge factor(GF) of about 5.1×105.