氧化锌微纳米结构的制备及新型光电器件的研制

发布时间：2018-10-31 08:29

【摘要】：Zn O是用来制作高效紫外光电器件最具发展潜力的材料,在发光二极管、激光二极管和紫外探测器等领域有广泛的应用。作为重要的直接带隙半导体,其禁带宽度为3.37e V,室温下自由激子束缚能是60me V,远高于Ga N的25me V和Zn S的38me V,也远高于室温热离化能(26me V),使得激子在室温条件下就可以发生复合发光。与其他宽禁带半导体材料相比,Zn O更有利于制作紫外光电器件。并且Zn O具有多种微纳米结构,这些微纳米器件也表现出优异的光电性能。目前,Zn O的研究已取得了一定的进展,但仍存在一些问题亟待解决,比如:异质结发光中心通常在p-Ga N与Zn O界面;带边发光红移;同质结制作困难等。本论文针对Zn O研究中存在的问题,制备了Zn O微纳米结构并制作了微纳米结构的光电器件。开展了如下创新性的工作:1.在ITO电极上采用溶胶凝胶的方法制备了直径为5nm的Zn O量子点,采用Zn O量子点作为发光层,p-Ga N作为空穴注入层,制作了Zn O量子点/p-Ga N异质结发光二极管。利用量子点的陷阱控制的空间电荷限制电流的行为,使发光二极管的发光中心集中在量子点层,得到了纯紫外发光的Zn O发光二极管,发光波长在382nm,半峰宽较窄。与先前报道的器件相比,Zn O量子点发光二极管具有高的发光强度和好的单色性。2.采用化学气相沉积的方法生长了高效绿色发光的Zn O微米线。Zn O微米线与p-Ga N构成的异质结,在p-Ga N端加正向电压时得到波长为395nm的紫外发光,在Zn O端加正向电压时得到发光峰位于450-700nm的橙色发光。与n-Ga N构成的异质结,在Zn O端加正向电压时得到波长为490nm的绿色发光。并分别详细的阐述了各种颜色发光的机理。3.采用氮等离子体处理的方法得到了氮掺杂的Zn O单晶。低温光致发光光谱中观察到受主束缚激子相关的发光,形成了NO受主能级,拉曼散射光谱中发现氧晶格的振动模式发生蓝移,处理后Zn O表面功函数变大,费米能级向价带移动,表明空穴浓度增加。这些结果都证明氮原子已经掺杂到Zn O晶格中。通过构造Zn O基同质结器件,得到了良好的I-V整流特性,表明获得了p型导电的N掺杂Zn O。4.采用磁控溅射和金属离子溅射的方法制备了Ag纳米颗粒修饰的Zn O薄膜紫外探测器。Zn O/Ag纳米颗粒/Zn O夹层结构在385nm到356nm表现出强的吸收增强,Ag纳米颗粒改善了Zn O薄膜的性能。Ag修饰的Zn O薄膜紫外探测器响应度提高了一个数量级,紫外可见抑制比提高了一个多量级。上升和下降时间明显减少。
[Abstract]:Zn O is the most promising material for making high efficiency ultraviolet photovoltaic devices. It has been widely used in light emitting diodes, laser diodes and ultraviolet detectors. As an important direct bandgap semiconductor, its band gap width is 3.37e V. the free exciton binding energy at room temperature is 60me V, which is much higher than Ga N's 25me V and Zn S's 38me V, and far higher than the room temperature thermal ionization energy (26me V),). At room temperature, the exciton can produce recombination luminescence. Compared with other wide band gap semiconductor materials, Zn O is more favorable for the fabrication of UV optoelectronic devices. And Zn O has a variety of micro-and nano-structure, these micro-nano devices also show excellent photoelectric performance. At present, some progress has been made in the study of, Zn O, but there are still some problems to be solved, such as: the luminescence center of heterojunction usually lies in the interface of p-Ga N and Zn O; the red shift of band edge luminescence; and the fabrication of homogeneous junction is difficult, etc. In order to solve the problems in the research of Zn O, Zn O microstructures and optoelectronic devices are fabricated in this paper. The following innovative work has been carried out: 1. Zn O quantum dots with diameter of 5nm were prepared by sol-gel method on ITO electrode. Using Zn O quantum dots as luminescent layer and p-Ga N as hole injection layer, Zn O quantum dots / p-Ga N heterojunction light-emitting diodes were fabricated. By using the space charge limiting current behavior controlled by quantum dot trap, the light-emitting center of the light-emitting diode is concentrated in the quantum dot layer, and a pure ultraviolet light-emitting Zn O light-emitting diode is obtained, the wavelength of which is 382 nm and the width of the half peak is narrow. Compared with the previously reported devices, Zn O QDs have high luminescence intensity and good monochromatic properties. 2. The heterojunction between Zn O micron line. Zn O micron line and p-Ga N was grown by chemical vapor deposition (CVD). UV luminescence at the wavelength of 395nm was obtained by adding a forward voltage to the p-Ga N terminal. When positive voltage is applied to the O terminal of Zn, the orange luminescence peak of 450-700nm is obtained. When the positive voltage is applied to the O terminal of n-Ga, the green luminescence of 490nm wavelength is obtained by the heterojunction with n-Ga N. The mechanism of various color luminescence is described in detail. 3. Nitrogen doped Zn O single crystals were obtained by nitrogen plasma treatment. In the low temperature photoluminescence spectra, the acceptor bound excitons were observed and the NO acceptor energy levels were formed. In the Raman scattering spectra, it was found that the vibrational mode of the oxygen lattice shifted blue, and the surface work function of Zn O became larger after treatment. The Fermi level moves to the valence band, indicating an increase in the hole concentration. These results show that the nitrogen atom has been doped into the Zn O lattice. Good I-V rectifying characteristics have been obtained by constructing Zn O-base homogenous junction devices. It is shown that p-type conductive N-doped Zn O. 4 has been obtained. Ag nanoparticles modified Zn O thin film UV detectors were prepared by magnetron sputtering and metal ion sputtering. Zn O/Ag nanoparticles / Zn O interlayer structure showed strong absorption from 385nm to 356nm. The Ag nanoparticles improved the performance of Zn O thin films, the responsivity of Ag modified Zn O thin films was increased by one order of magnitude, and the UV / vis inhibition ratio was increased by one order of magnitude. The time of rising and falling was obviously reduced.
【学位授予单位】：中国科学院研究生院(长春光学精密机械与物理研究所)
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TB383.1;O614.241

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