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通过激光分子束外延(LMBE)和热蒸发技术制备了基于ZnS纳米薄膜的Al/ZnS/ITO/玻璃器件,通过原子力显微镜(AFM)对ZnS表面薄膜形貌进行表征,采用Keithley 2400测量其电学特性,分别研究了扫描电压、ZnS薄膜厚度及不同温度的退火处理对器件电学特性的影响。实验结果表明:在不同的扫描电压作用下,器件均表现出稳定的负微分电阻特性,且其阻值随扫描电压的变化呈现出高低电阻两种状态,器件具有明显的记忆特性。适当减小ZnS薄膜的厚度或对器件进行400℃退火处理,均可有效减小低阻态的阻值,提高器件的峰-谷电流比率,进而优化器件的记忆特性。最后,基于能谷散射理论,对器件的负微分电阻特性进行了合理解释,理论和实验结果吻合较好。
Al / ZnS / ITO / glass devices based on ZnS nanostructured films were prepared by laser molecular beam epitaxy (LMBE) and thermal evaporation techniques. The surface morphology of ZnS films was characterized by atomic force microscopy (AFM) and their electrical properties were measured by Keithley 2400 The effects of annealing voltage, thickness of ZnS film and annealing at different temperatures on the electrical properties of the devices were investigated. The experimental results show that the device exhibits stable negative differential resistance under different scan voltages, and its resistance exhibits two states of high and low resistance as the scan voltage changes. The device has obvious memory characteristics. Appropriate reduction of the thickness of the ZnS thin film or annealing the device at 400 ° C can effectively reduce the resistance of the low resistance state and improve the peak-to-valley current ratio of the device to further optimize the memory characteristics of the device. Finally, based on the theory of energy valley, the negative differential resistance of the device is reasonably explained, and the theoretical and experimental results are in good agreement.