氧化锌纳米材料压电器件的构建及界面调控研究

发布时间：2018-06-07 08:26

本文选题：一维氧化锌纳米材料 + 纳米发电机　；参考：《北京科技大学》2015年博士论文

【摘要】：氧化锌(ZnO)纳米材料同时具备优异的半导体性能和压电性能。利用维ZnO纳米材料的压电性能构建的压电纳米发电机和半导体与压电的耦合特性构建的压电电子器件已成为纳米半导体器件研究领域的新方向。以应用为导向,利用材料的结构特点构建高性能的实用性压电电子器件,探究压电电子效应对器件界面处载流子行为的调控规律等,已成为当前的研究热点。本研究通过优化生长工艺,控制合成出多种一维ZnO纳米材料。构建了单根铟掺杂氧化锌(In-ZnO)纳米带柔性应变传感器,利用有限元模拟分析了器件的应变响应机理；构建了ZnO纳米线阵列振动传感器,研究了在自驱动模式和外加电压模式器件的响应机理,实现了低频机械振动信号的探测,并应用于人体脉搏振动的探测；构建了Pt/Al2O3/ZnO肖特基结,研究了应变对器件界面电阻、接触势垒以及界面光生载流子的调控规律,揭示了压电电子效应对载流子的界面调控机制。采用气相沉积法制备了In-ZnO纳米带,纳米带宽度约为1μm、厚度约为200nm、长度大于100μm,生长方向为[2110],上表面为(0001)极性面。采用水热合成法通过工艺优化制备了高度为10μm的ZnO纳米线阵列和高密度ZnO纳米线阵列薄膜。采用氢氧化钠和醋酸锌的乙醇溶液交替涂覆,在柔性衬底上制备了ZnO晶种层,生长了ZnO纳米线阵列。采用In-ZnO纳米带构建了柔性压电电子应变传感器,分别实现了静态和动态应变检测。器件的电流电压曲线呈双肖特基整流特性。静态应变检测时,电流电压曲线在压缩应变时上移,拉伸应变时下移。采用有限元模拟分析了In-ZnO纳米带在轴向应变下的压电势分布,发现在泊松效应的作用下,轴向应变使In-ZnO纳米带在极性上表面产生压电势,调控了源漏极肖特基势垒高度,产生应变响应电流。周期性应变动态检测结果说明器件具有清晰准确的响应电流,压缩应变时应变系数达到4036。采用柔性Pt电极与ZnO纳米线阵列构建了肖特基型振动探测器。器件可在无外加工作电压的自驱动模式和外加工作电压模式实现对低频机械振动信号的探测。自驱动模式中,器件的响应电流是通过纳米线阵列产生的压电势改变界面处的费米能级高度使外电路电荷定向移动形成的；对于应力为1KPa的机械振动,响应电流为10nA,振动探测相对误差小于0.37%。外加工作电压模式下,压电势对肖特基势垒的调控和压电阻效应的共同作用提升了响应电流。当工作电压为+3V时,器件对应力为1KPa的机械振动的响应电流相对变化率提升到3700%,探测相对误差小于0.91%,并成功应用于人体脉搏振动的探测。采用Pt/AhO3/ZnO结构的MIS型肖特基结,研究了压电电子效应对金属/ZnO肖特基结的界面调控机理。采用原子层沉积方法在ZnO纳米线表面制备的Al2O3绝缘层,有效降低了表面态对接触势垒的影响,阻止了光照下Pt表面热电子跃迁对压电电子效应界面调控作用的影响。通过研究压应变下界面接触势垒、界面电阻和界面光生载流子的变化,发现随着压缩应变增加到-1.0%时,肖特基势垒提高了147meV,界面载流子分离效率提升了2.7倍,界面电阻显著提升。揭示了压应变对ZnO金属肖特基结的界面调控机制为：压应变在界面处产生的负极化电场排斥空间电荷区载流子向ZnO内部的准平衡区移动,降低了空间电荷区的载流子浓度,展宽了空间电荷区的宽度,提高了内建电场强度,抬高了界面势垒高度。
[Abstract]:Zinc Oxide (ZnO) nanomaterials have excellent semiconductor properties and piezoelectric properties. Piezoelectric nanoscale and piezoelectric devices constructed by the piezoelectric properties of ZnO nanomaterials have become a new direction in the research field of nano semiconductor devices. The construction of high performance piezoelectric electronic devices and the study of the regulation of the piezoelectric effect on the carrier behavior at the interface of the device have become a hot spot of research.
In this study, a variety of one-dimensional ZnO nanomaterials were synthesized by optimizing the growth process. A single indium doped Zinc Oxide (In-ZnO) nanoscale flexible strain sensor was constructed. The strain response mechanism of the device was analyzed by finite element simulation, and a ZnO nanowire array vibratory sensor was constructed. The self driving mode and external voltage mode were studied. The response mechanism of the type device has realized the detection of low frequency mechanical vibration signals and applied to the detection of human pulse vibration. The Pt/Al2O3/ZnO Schottky junction was constructed. The regulation of the interface resistance, the contact barrier and the interface photogenerated carrier were studied. The mechanism of the piezoelectric electron effect on the carrier interface was revealed.
In-ZnO nanoribbons were prepared by gas phase deposition. The width of the nanoribbons was about 1 mu m, the thickness was about 200nm, the length was more than 100 mu m, the growth direction was [2110], and the upper surface was (0001) polar surface. By the hydrothermal synthesis process, the high density ZnO nanowire array and the high density ZnO nanowire array film were prepared by the process of hydrothermal synthesis. The sodium hydroxide was used. The ZnO seed layer was grown on flexible substrates and the ZnO nanowire arrays were grown on flexible substrates by alternately coating with ethanol solution of zinc acetate.
The flexible piezoelectric electronic strain sensor is constructed by using In-ZnO nanometers. The static and dynamic strain detection is realized. The current voltage curve of the device is double Schottky rectifier. The current voltage curve moves up when the static strain is detected, and the tensile strain moves down. The finite element simulation is used to analyze the In-ZnO nanometers. Under the axial strain pressure potential distribution, it is found that under the effect of Poisson effect, the axial strain produces the piezoelectric potential on the surface of the In-ZnO nanometers on the polar surface, regulates the Schottky barrier height of the source drain and produces the strain response current. The periodic strain dynamic detection results show that the device has a clear and accurate response current and the strain time strain is compressed. The coefficient is 4036.
A Schottky type vibration detector is constructed with a flexible Pt electrode and a ZnO nanowire array. The device can detect the low frequency mechanical vibration signals in the self driving mode without the external working voltage and the external working voltage mode. The Fermi energy level makes the charge of the external circuit formed; for the mechanical vibration of the stress 1KPa, the response current is 10nA, the relative error of the vibration detection is less than 0.37%. and the working voltage mode, the joint action of the piezo potential to the Schottky barrier and the pressure resistance effect enhances the response current. When the working voltage is +3V, The relative change rate of the response current of the mechanical vibration of 1KPa is raised to 3700%, the relative error of the detection is less than 0.91%, and it is successfully applied to the detection of the pulse vibration of the human body.
Using the MIS type Schottky junction of Pt/AhO3/ZnO structure, the interface regulation mechanism of the piezoelectric electron effect on the metal /ZnO Schottky junction is studied. The Al2O3 insulating layer prepared on the surface of the ZnO nanowire by the atomic layer deposition method can effectively reduce the effect of the surface state on the contact barrier and prevent the piezoelectric electron effect from the thermal electron transition of the Pt surface to the piezoelectric electron effect. By studying the influence of interface control. By studying the interface contact barrier under the pressure strain, the interface resistance and the interfacial photogenerated carrier, it is found that the Schottky barrier is increased by 147meV with the compression strain increasing to -1.0%, the interfacial carrier separation efficiency is increased by 2.7 times and the interfacial electrical resistance is significantly improved. The pressure strain is revealed to the ZnO metal Schott. The interface regulation mechanism of the base junction is that the negative polarization electric field produced by the compressive strain at the interface rejects the shift of the space charge carrier into the quasi equilibrium region within the ZnO, reducing the carrier concentration in the space charge region, broadening the width of the space charge area, improving the strength of the internal electric field and raising the height of the interface barrier.
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TN384;TB383.1

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