摘 要

氧化锌（ZnO）是一种典型的Ⅱ-Ⅵ族化合物的发光半导体材料，室温下一般为六方纤锌矿结构，是制作蓝绿光，紫外光等短波长光源优异的候选材料，并且还可以用来制备多种发光器件，如透明电极，平面光波导，紫外发光器件，紫外光探测器等^[1-3]。随着科学技术的飞速发展，人们对器件的发光要求日益提高，为了获得更优异的ZnO光源材料，人们将目光放在了ZnO基材料的掺杂改性方面^[7-9]，MgO的禁带为7.8ev，大于ZnO的禁带（ZnO的禁带为3.37ev），Mg² 具有的离子半径和Zn² 的离子半径相近（Mg² 的离子半径：0.057nm ；Zn² 的离子半径：0.060nm），不同的掺杂量形成的Zn_xMg_1-xO(0≤x≤1)合金的禁带可以在3.37-7.8ev范围之间连续调节，所以Zn_xMg_1-xO(0≤x≤1)合金材料已经成为了研究的热点^[2]。但是在ZnMgO禁带连续可调的“能带工程”中存在著名的单相形成问题，即MgO为立方岩盐结构，ZnO为六方纤锌矿结构，当掺杂量x≤0.37时，Zn_xMg_1-xO合金为单相的六方纤锌矿结构，当x≥0.37时，Zn_xMg_1-xO合金出现分相，从而会影响到Zn_xMg_1-xO合金的光学性能^[1-4]。

本文采用溶胶凝胶法制备出Zn_xMg_1-xO合金薄膜，并探究退火温度、退火方式、缓冲层等对ZnMgO合金薄膜晶体结构及光学性能的影响，以制备单相的高Mg掺杂量的Zn_xMg_1-xO合金薄膜。利用XRD、AFM、紫外可见透射光谱和吸收光谱等对所制备的薄膜材料的相组成、形貌、光学性能等进行表征。

实验结果表明：（1）.退火方式对溶胶凝胶法制备的Zn_1-xMg_xO合金薄膜材料的晶体结构、光学性能有重要的影响。在随炉退火、快速退火、层层退火三种退火方式中，快速退火制备的Zn_1-xMg_xO合金薄膜材料没有发生相的分离，且光学性能最佳。（2）.纯ZnO缓冲层，低Mg掺量缓冲层对溶胶凝胶法制备的高Mg掺杂Zn_1-xMg_xO合金薄膜相的分离有抑制作用，且以纯ZnO作为缓冲层的高Mg掺杂的Zn_1-xMg_xO合金薄膜样品的禁带宽度为3.66ev左右。（3）.浓度梯度缓冲层对溶胶凝胶法制备的Zn_1-xMg_xO合金薄膜材料相的分离抑制作用更显著，同样以浓度梯度缓冲层的高Mg掺杂Zn_1-xMg_xO合金薄膜几乎没有相的分离，此时制备的Zn_1-xMg_xO合金薄膜样品的禁带宽度为3.72ev左右。

关键词：Zn_1-xMg_xO；溶胶凝胶法；退火温度；缓冲层；能带调节

Abstract

Zinc oxide (ZnO) is a kind of Ⅱ-Ⅵ compound semiconductor materials，it has a standard wurtzite structure.In the blue and green light, such as short wave ultraviolet light，hair light source has obvious advantages，Can be used for the preparation of a variety of light-emitting devices，Such as Planar Transparent electrode，optical waveguide，UVdetector, ultraviolet light-emitting devices, etc^[1-3].With science and technology developmenting,People light requirements for devices,people set his sights on doping modification of ZnO based materials^[7-9]，MgO style of forbidden band width is 7.8ev,Is greater than the forbidden band width of ZnO (ZnO forbidden band width is 3.37 ev).Magnesium has a similar ion radius with zinc radius (magnesium ion radius: 0.057 nm; Zn ion radius: 0.060 nm), The solid solubility of Mg in ZnO crystal body is small,According to the different form of doping amount Zn_xMg_1-xO(0≤x≤1) alloy of forbidden band width can be 3.37-7.8 ev can be continuous to adjust,Now MgO style doped ZnO materials has become the research hot spot. But the ZnMgO forbidden band width adjustable for "energy band engineering" famous ingle-phase formation problems,The ZnO as wurtzite structure，MgO as rock-salt structure，When the doping amount x≤0.37，Zn_xMg_1-xO alloy for single-phases wurtzite structure,When x≥0.37 Zn_xMg_1-xO alloy appear MgO style face-centered cubic phase and ZnO as wurtzite phase,Which would affect the optical properties of the Zn_xMg_1-xO alloy^[1-4].

This article Prepared Zn_xMg_1-xO alloy thin film by sol gel method，And explore how did annealing temperature, annealing method, buffer layer affect on the crystal structure and optical properties of ZnMgO alloy film, to preparao single phase in high Mg doped Zn_xMg_1-xO alloy membrane.Using XRD, AFM, UV-Vis transmission spectra and absorption spectra for the preparation of thin film materials such as phase composition, So morphology and optical properties were characterized.

The experimental results show that:（1）.Annealing way has an important influence to optical properties and crystal structure of sol gel prepared Zn_xMg_1-xO films, among with layers of annealing, rapid annealing, along with the mode of furnace temperature annealing,Crystal structure of rapid annealing Zn_xMg_1-xO alloy thin film material almost has no phase separation, optical properties is the best.（2）.Low Mg buffer layer of sol-gel prepared high Mg doped Zn_xMg_1-xO alloy membrane phase separation of inhibition,And pure ZnO as a buffer layer high Mg doped Zn_xMg_1-xO alloy film almost no phase separation,The preparation of Zn_xMg_1-xO alloy thin film samples of the forbidden band width is about 3.66 ev.（3）.Component hierarchical buffer layer of sol gel method effect Zn_xMg_1-xO alloy thin film material phase separation are more significant ,For the high concentration gradient of the buffer layer Mg doped Zn_xMg_1-xO alloy thin film almost has no phase separation,the preparation of Zn_xMg_1-xO alloy thin film samples of the forbidden band width is about 3.72 ev.

Keywords：Zn_1-xMg_xO；Sol -gel method；The annealing temperature; Buffer layer; Band-gap turning

目 录

第一章 绪论 1

1.1 引言 1

1.2 ZnO材料的介绍 1

1.2.1 ZnO材料的晶体结构及基本性质 1

1.2.2 ZnO的发光特性 4

1.3Zn_1-xMg_xO半导体材料的研究现状 5

1.3.1 Zn_1-xMg_xO的结构 5

1.3.2 Zn_1-xMg_xO的发光特性 6

1.3.3Zn_1-xMg_xO研究进展及面临的挑战 7

1.4 Zn_1-xMg_xO薄膜的制备方法 8

1.4.1磁控溅射法 8

1.4.2金属有机物气相沉积 9

1.4.3脉冲激光沉积(PLD)法 9

1.4.4分子束外延(MBE)法 10

1.4.5 溶胶凝胶法 10

1.5 研究目的及主要研究内容 11

第2章 Zn_1-xMg_xO材料的制备与表征 13