论文总字数：16974字

摘 要

ZnO线性电阻是新型N型半导体材料。ZnO线性电阻具有成本低、可调的电阻率、高的通流密度、较小的阻温系数等特点，它在电路保护系统、储能器、接地电阻、释能电阻等方面广泛应用，随着我国电子、电力行业的迅猛发展，研发出性能良好的ZnO电阻已经成为一个热点。

因为在制备过程中掺杂了其他元素的氧化物，所以在烧结过程中会发生复杂的固相反应，对烧成后的材料造成不良影响。导致这类功能陶瓷产生了重复率低、性能不稳定性等问题。此外，到目前为止，国内外研究者对于ZnO线性电阻的研究仍处于实验阶段，对其多方面性能的改善并没有系统的研究。现在对于性能稳定的电阻材料的需求仍处于上升阶段，然而目前的研究现状已经不满足实际需要。

针对以上问题，本文拟采用传统固相烧结法制备ZnO线性电阻陶瓷，以ZnO- MgO-Al₂O₃三元体系为基础配方，尝试在ZnO线性电阻陶瓷基础上掺杂Nb₂O₅及稀土氧化物La₂O₃，经过非线性系数，晶界势垒高度，电阻频率等测试，研究Nb₂O₅及La₂O₃对ZnO线性电阻陶瓷的影响，研究高频下电学性能，以提高ZnO线性电阻综合电学性能及稳定性。

结果表明，掺杂Nb₂O₅可以减小ZnO线性电阻的电阻率，降低晶界势垒高度和非线性系数，增加高频下电阻率的稳定性；1.5wt.% Nb₂O₅掺杂下ZnO线性电阻表现出优异的综合性能：其电阻温度系数为-0.35×10^-3/℃，非线性系数为1.04，晶界势垒高度为0.004eV。掺杂La₂O₃可以降低ZnO线性电阻的气孔率，提高其致密度，降低晶界势垒高度和非线性系数；ZnO线性电阻的最佳La₂O₃掺杂量是1.5%，最佳烧结温度是1390℃，制备出的ZnO线性电阻的电阻率为423Ω·cm，非线性系数为1.13，阻温系数为2.45×10^-4/℃。

关键词：ZnO线性电阻 非线性系数 电学性能 Nb₂O₅ La₂O₅

Effect of Nb₂O₅ and La₂O₃ doping on the properties of ZnO linear resistance

Abstract

ZnO linear resistance is a kind of n-type semiconductor material, which takes ZnO as the main material, doped with other elements (such as MgO, Al₂O₃, TiO₂, etc.) and sintered at high temperature. ZnO linear resistor has the characteristics of low cost, adjustable resistivity, high current density, small resistance temperature coefficient, etc. it is widely used in circuit protection system, energy storage, grounding resistance, energy release resistance, etc. with the rapid development of China's electronics and power industry, the research and development of ZnO Resistor with good performance has become a hot spot.

Because of doping oxides of other elements in the preparation process, complex solid-state reactions will occur in the sintering process, which will have adverse effects on the sintered materials. This leads to the low repetition rate, performance instability and other problems of this kind of functional ceramics. In addition, up to now, researchers at home and abroad are still in the experimental stage of ZnO linear resistance, and there is no systematic study on its performance improvement. At present, the demand for resistance materials with stable performance is still on the rise. However, the current research situation has not met the actual needs.

In view of the above problems, this paper plans to use the traditional solid-phase sintering method to prepare ZnO linear resistance ceramics- Based on the MgO-Al₂O₃ ternary system, Nb₂O₅ and rare earth oxide La₂O₃ were doped on the basis of ZnO linear resistance ceramics. The effects of Nb₂O₅ and La₂O₃ on ZnO linear resistance ceramics were studied through the tests of nonlinear coefficient, barrier height of grain boundary, resistance frequency and so on. In order to improve the comprehensive electrical performance and stability of ZnO linear resistor, its high frequency electrical performance was studied.

The results show that Nb₂O₅ doping can reduce the resistivity of ZnO linear resistance, reduce the barrier height and nonlinear coefficient of grain boundary, and increase the stability of resistivity at high frequency; 1.5wt.% Nb₂O₅ doping ZnO linear resistance shows excellent comprehensive performance: the temperature coefficient of resistance is - 0.35 × 10^-3 / ℃, the nonlinear coefficient is 1.04, and the barrier height of grain boundary is 0.004ev. Doping La₂O₃ can reduce the porosity of ZnO linear resistance, increase its density, reduce the barrier height and nonlinear coefficient of grain boundary; doping 1.5wt% La₂O₃ sintering at 1390 ℃ has good linear resistance performance, its resistivity is 423 Ω· cm, resistance temperature coefficient is 2.45 × 10^-4 / ℃, nonlinear coefficient is 1.13.

Key words: ZnO linear resistance ;Nonlinear coefficient ; Electrical performance ;

Nb₂O₅; La₂O₅

目 录

摘 要 I

Abstract III

第一章 绪论 1

1.1 ZnO线性电阻的研究背景 1

1.2 ZnO线性电阻的研究现状 1

1.3 添加剂对ZnO线性电阻性能的影响 2

1.4 研究目的及意义 2

第二章 ZnO线性电阻的制备及其表征 4

2.1材料制备 4

2.1.1实验试剂 4

2.1.2实验仪器 4

2.1.3工艺流程 5

2.1.4实验步骤 7

2.2 ZnO线性电阻的表征方法 8

2.2.1体积密度及气孔率 8

2.2.2 非线性系数 9

2.2.3 电阻温度系数 9

第三章 Nb₂O₅含量对ZnO线性电阻微观结构和电学性能的影响 10

3.1 引言 10

3.2 实验内容设计 10

3.3 结果与谈论 10

3.4 本章小结 16

第四章 La₂O₃含量对ZnO线性电阻微观结构和电学性能的影响 18

4.1 引言 18

4.2 实验内容设计 18

4.3 结果与谈论 18

4.4 本章小结 21

第五章 结论和展望 23

5.1 结论 23

5.2 展望 23

参考文献 24

致谢 26

第一章 绪论

在科学研究日益发展的现代，线性电阻在电子元器件的应用范围扩大，成为一个新的研究方向。制备线性电阻的材料有碳基材料，金属基材料和陶瓷基材料。其中ZnO线性陶瓷电阻具有体积小重量轻的特点，相比于传统电阻，它的电阻率可调，即使在高温条件下工作，电阻率波动范围也较小，可以吸收大量能量密度。此外，它的电源-电压特性呈线性。

1.1 ZnO线性电阻的研究背景

氧化锌材料是一种半导体材料，具有很高的激子束缚能，通过掺杂能使ZnO薄膜具有较高的透光率^[1]，并且掺杂能使ZnO对气体有良好的敏感性，因此氧化锌材料可以制成光电材料和气敏材料。此外，ZnO薄膜还具有较高的电导率，是一种很好的压电性质材料，利用此优点可制成ZnO压敏电阻^[1]。ZnO压敏电阻在现代生活中有着无可替代的作用。ZnO线性电阻正是在ZnO压敏电阻的基础上发展起来的。

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