【作者】 辛萍；

【导师】 张庆瑜；

【作者基本信息】 大连理工大学 ， 凝聚态物理， 2007， 硕士

【摘要】 氧化锌（ZnO）是新一代的Ⅱ-Ⅵ族宽带半导体材料，具有纤锌矿晶体结构，禁带宽度为3．37eV，激子束缚能为60 meV，可以实现室温下的受激发射。ZnO薄膜具有良好的透明导电性、压电性、光电性、压敏性，并且易于与多种半导体材料实现集成化。因此，ZnO材料具有广泛的应用，可以制成表面声波谐振器，压电器件，透明导电膜以及GaN蓝光薄膜的过渡层等。在ZnO光电特性研究中，人们关注薄膜的实用化，目前ZnO研究领域的关注焦点是ZnO结型器件的制备。而要实现制备器件的目标，需要对ZnO实现可靠的p型掺杂，还要有效地调节ZnO能带。本文采用RF反应磁控溅射方法在Si（001）、Si（111）和石英衬底上生长了ZnO／MgO多量子阱以及Zn_1-x,Mg_xO及Zn_1-xCd_xO合金薄膜。利用X-射线衍射、电子探针、透射光谱和光致荧光光谱对薄膜的结构、成分和光学特性进行了检测与分析。论文分为以下两个部分：Ⅰ采用反应射频磁控溅射方法，在Si（100）基片上制备了具有高c轴择优取向的ZnO／MgO多量子阱。利用X-射线反射、X-射线衍射、电子探针和光致荧光光谱等表征技术，研究了ZnO／MgO多量子阱的结构、成份和光致荧光特性。多量子阱的调制周期在1．85～22．3 nm之间，所制备的多量子阱具有量子限域效应，导致了室温光致荧光峰的蓝移，并观测到了量子隧穿效应引起的荧光效率下降。建立了基于多声子辅助激子复合跃迁理论的室温光致荧光光谱优化拟合方法，拟合结果发现，ZnO／MgO比ZnO／ZnMgO多量子阱具有更大的峰位蓝移，探讨了导致光致荧光光谱展宽的可能因素。Ⅱ利用射频反应磁控溅射技术，在Si（111）和石英基片上生长具有c轴择优取向的Zn_1-x,Mg_xO（0=x=0．62）和Zn_1-xCd_xO（0≤x≤0．10616）合金薄膜。探讨了Zn_1-xMg_xO合金薄膜的晶体结构随掺入Mg元素的关系，掺入Mg元素能够有效地调节光学带隙宽度；随着薄膜中Mg含量的增加，带隙宽度随之增大；对Zn_1-xMg_xO薄膜退火的结果，退火对Zn_1-xMg_xO薄膜的晶体取向基本没有影响，但退火改善了薄膜的结晶性能，同时退火减弱了薄膜中的缺陷发光。在Zn_1-xCd_xO薄膜的研究方面，对Si（111）基片采用先沉积金属Ti层、室温沉积znO再经退火的基片处理方法，然后再生长Zn_1-xCd_xO合金薄膜，所制得的Zn_1-xCd_xO薄膜具有c轴择优取向；纤锌矿（002）衍射峰的半峰宽随着Cd含量的增加而明显增加；薄膜在Cd含量x＜0．10616的范围内能够保持纤锌矿结构，没有出现比较明显的Cd的相分离现象。更多还原

【Abstract】 ZnO is aⅡ-Ⅵwide-band-gap （～3.3eV at room temperature） semiconductor with ahexagonal wurtzite structure. In terms of optoelectronics, its direct band gap and a largeexciton banding energy （60meV） should in principle lead to low thresholds for optical gaineven at room temperature. Due to the excellent physical and chemical properties, they can beintegrated with many semiconductor materials readily. ZnO films also have many realizedand potential applications such as surface acoustic wave devices, ultraviolet photodetectors,gas sensors, light emitters, transition layer for GaN and transparent conductors for display, etc.Now, a crucial step in designing ZnO-based optoelectronic devices is the realization ofband-gap engineering to create barrier layers and quantum wells in device heterostructures.This work is focus on the structural and optical properties of the ZnO-based materials, asfollow: ZnO/MgO quantum wells and ZnO-based films were grown on Si（100）（111） andquartz substrates with a RF reactive magnetron sputtering method. We use XRD, EPMA,transmission spectrum and photoluminescence analysis to test the microstructure, content andthe optical properties of the ZnO-based materials. This work is focus on the structural andoptical properties of the ZnO-based materials, as follow:ⅠWurtzite ZnO/MgO superlattices were successfully grown on Si （001） substrates at 750℃with a radio-frequency reactive magnetron sputtering method. X-ray reflection and diffraction,electronic probe and photoluminescence analysis were used to characterize the multiplequantum wells （MQWs）. The results showed the periodic layer thickness of the MOWs to be1.85 to 22.3 nm. The blueshift induced by quantum confinement effect was observed. Afitting method based on the least square theory was used to deduce the zero phonon energy ofthe exciton from the room-temperature photoluminescence. It was found that MgO barrierlayers had a much larger offsets than ZnMgO. The fluctuation of periodic layer thickness ofthe MOWs was suggested to be a possible reason causing the photoluminescence broadening.ⅡZn_1-xMg_xO films （0=x=0.62） and Zn_1-xCd_xO films （0=x=0.10616） were grown on Si（111）and quartz substrates with RF reactive magnetron sputtering method. In the Zn_1-xMg_xO films,a strong c-axis orientation had been obtained at 750℃. We discussed the relationshipbetween crystal property and Mg incorporation. In addition, the Optical Band Gap of Zn_1-xMg_xO films is adjusted by Mg incorporation. The Optical Band Gap of the films had thesame pace with the increase of Mg incorporation. After annealing at 700℃, the orientation ofthe films had not been influenced so that annealing improved the crystal property ofZn_1-xMg_xO films. The defect photoluminescence was also weakened after annealing.Zn_1-xCd_xO films had a strong c-axis orientation with a Ti layer and ZnO layer deposited onthe substrate. The percentage of composition of Cd was between 0 and 10.616％. The FWHMof （002） diffraction peak of the wurtzite phase was in the same trend with the increace of Cdcontent. The films remained a hexagonal wurtzite structure within Cd incorporation x=10.616 with no obvious phase separation.更多还原