【作者】 陈功兵；

【导师】 张化宇；

【作者基本信息】 哈尔滨工业大学 ， 材料物理与化学， 2009， 硕士

【摘要】 氧化锌(ZnO)是一种典型的Ⅱ-VI族宽带隙化合物半导体材料,具有六方纤锌矿结构,它的禁带宽度为3.37eV,激子束缚能为60meV。氧化锌晶体在c轴垂直面上具有对称的电学性质和弹性,而在c轴方向择优取向的多晶薄膜具有单晶体似的压电性和光电性质。此外,ZnO在晶格常数和热膨胀系数上与GaN最为接近, ZnO在a轴向与GaN的失配度是1.9% ,在c轴向与GaN的失配度仅为0.4%,因此,高质量的ZnO薄膜能作为GaN薄膜的缓冲层。这些突出的物理特性和平整均匀的表面形貌,使得ZnO薄膜可以广泛应用于各领域当中。本文以醋酸锌(Zn(CH3COO)2·2H2O)为前驱体,乙二醇甲醚(CH3OCH2CH2OH)为溶剂,乙醇胺(HOCH2CH2NH2)作为稳定剂,采用溶胶—凝胶法在蓝宝石基片上制备了ZnO薄膜。主要研究了溶胶浓度(0.5mol/l、0.75mol/l、1mol/l)、退火温度(500-1000℃)以及薄膜厚度(1层膜、2层膜、3层膜、5层膜、7层膜、8层膜、10层膜)对薄膜晶体结构、结晶状况、表面形貌的影响,利用X射线衍射(XRD)、扫描电子显微镜(SEM)。原子力显微镜(AFM)、光致发光光谱仪(PL)等对制备的ZnO薄膜进行了表征和性能研究。研究表明:采用溶胶-凝胶法所制备的ZnO薄膜为纤锌矿型结构,溶胶浓度为0.75mol/l时薄膜C轴取向性好,晶体颗粒均匀致密,空位及缺陷浓度不高。相同条件下(溶胶浓度0.75mol/l、提拉速度18mm/min、退火条件:900℃/2h),晶粒尺寸随着薄膜层数的增多慢慢变大,(002)衍射峰强度在5层膜之前随着层数的增多而增强,但在5层膜以后有所削弱,使得氧化锌薄膜的择优取向性先变大再变小,说明5层膜的薄膜厚度最佳。薄膜(002)衍射峰的强度及晶粒尺寸随退火温度的升高而增大,(002)面的择优取向性也随之变强,900℃时薄膜结构综合性能最好,温度太高薄膜结构孔洞较多,致密性变差且容易与衬底发生反应污染薄膜。更多还原

【Abstract】 ZnO is a wide band gap semiconductor material inⅡ-Ⅵfamily, which with Wurtzite crystal structure, The band gap and the exciton bound energy of ZnO are 3.37eV and 60meV, Respectively, ZnO crystal has symmetrically electrical properties and flexibility on the vertical plane of c-axis,while the polycrystalline film with preferential c-axis orientation has the same piezoelectric and photoelectrical properties as single-crystal film. Otherwise, ZnO is very close to GaN in the lattice constant and thermal expansion coefficient, the mismatch of ZnO between GaN in a-axial is about 1.9% and in c-axial is only about 0.4%, Therefore, ZnO thin film with high-quality can play the role of the buffer layer of GaN thin films.Those outstanding physical property and even appearance of surface make ZnO film be widely applied to many industries.A series of ZnO films of different conditions have been deposited on sapphire substrates using sol–gel technique: different concentration of sol (0.5mol/l,0.75mol/l,1mol/l); different thickness of thin film (1layer, 2 layers, 3layers, 5layers, 7layers, 8layers, 10layers); different annealing temperature (500-1000℃). The effects of those conditions on the structural and optical properties have been investigated use X-Ray Diffraction(XRD)、Scanning Electron Microscopy(SEM)、Atomic Force Microscope(AFM) and Photoluminescence spectra(PL).The results indicate that the ZnO thin film has good c-axis orientation、uniform grain size、compact structure and small concentration of vacancies and defects when the concentration of sol was 0.75mol/l. Under the same conditions(CZn+:0.75mol/l, pulling rate: 18mm/min, annealing temperature: 900℃), the grain size of thin film increased with the increasing of film layers, ZnO thin film has the best (002) -oriented when the thickness of film was 5 layers. The intensity of (002) diffraction peak and grain size increased with the increasing of annealing temperature, (002)-oriented of ZnO thin film also become better with the increasing of annealing temperature, the ZnO thin film has the best structure properties when the annealing temperature was about 900℃. In addition, high-temperature annealed sapphire substrates could help improving the structure properties of ZnO thin film. Finally, we can make the conclusion that ZnO thin film deposited on annealed sapphire substrates by sol-gel method which has the best structural and optical properties when the concentration of sol was 0.75mol/l、the thickness was 5 layers、the annealing temperature was 900℃更多还原