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题名	具有单一吸收边的混相ZnMgO薄膜及其紫外探测器件的制备和特性研究
作者	范明明
学位类别	博士
答辩日期	2015-05
授予单位	中国科学院大学
导师	申德振
关键词	混相ZnMgO a-Al2O3 单一吸收边 紫外探测器
其他题名	Fabrication and Characteristics of Mixed-phase ZnMgO Thin Films with Single Absorption Edge and Their Ultraviolet Photodetectors
学位专业	凝聚态物理
中文摘要	ZnMgO基材料具有宽的带隙调节范围（从3.37 eV到7.8 eV）、高的电子饱和漂移速度、强的抗辐射能力、匹配的单晶衬底（ZnO和MgO）、低的缺陷密度、容易合成、无毒无害、资源丰富和环境友好等优于窄带隙半导体和其他宽带隙半导体的材料性质，使其成为紫外探测的候选材料之一。低的暗电流和高的响应度一直是ZnMgO紫外探测器的追求。六角相ZnMgO 紫外探测器通常具有较高的响应度，然而暗电流却较大；立方相ZnMgO 紫外探测器虽然具有较低的暗电流，但是响应度却较低。混相ZnMgO由于同时具有六角相和立方相ZnMgO，其紫外探测器有望同时具有两者的优势。目前，已报到的混相ZnMgO 紫外探测器通常具有较高的响应度，器件的暗电流依然较大。更重要的是，由于混相薄膜具有两个区分明显的吸收边导致器件具有两个探测带并且探测截止边不可控。这些问题限制了混相ZnMgO紫外探测器的进一步应用。针对目前混相ZnMgO紫外探测器具有双探测截止边以及暗电流较大等问题，本论文进行了细致的研究并取得了一些突破性的成果，具体如下： （1）针对目前混相ZnMgO薄膜具有两个区分明显的吸收边这一问题，我们利用MBE技术并采用与ZnO和MgO都具有较小晶格失配的a-Al2O3作为衬底，在国际上首次实现了具有单一吸收边的混相ZnMgO薄膜，其吸收边可从3. 9 eV到4.8 eV范围内可调。 （2）我们利用光刻和湿法刻蚀工艺，在具有单一吸收边的混相ZnMgO薄膜上实现了具有单一探测带的MSM结构混相ZnMgO紫外探测器，其探测截止边可以从325 nm到275 nm范围内可调。器件具有较低的暗电流（40 V下，暗电流为8 pA~130 pA）以及较高的响应度（40 V下，峰值响应度为9 A/W~410 A/W）。此外，器件的紫外可见抑制比在3个量级以上，响应时间为37 ms~1 s。器件具有较低的暗电流与本征高阻的立方相ZnMgO以及大量的六角相和立方相ZnMgO之间的异质结晶粒间界有关；器件具有较高的响应度与大量的异质结晶粒间界和体内深缺陷充当空穴陷阱，延长空穴寿命有关。 （3）同其他ZnMgO器件相比，我们的混相ZnMgO器件具有更好的综合性能，即：较低的暗电流、较高的响应度、较高的可见抑制比以及相对快速的响应时间。高性能的混相ZnMgO紫外探测器的实现将对其在紫外探测领域的发展与应用具有巨大的指导意义。
英文摘要	ZnMgO-based materials possess more excellent material characteristics over narrow bandgap and other wide bandgap semiconductors, including wide range of tunable bandgap (3.37 eV to 7.8 eV), high electron saturation velocity, high radiation hardness, lattice-matched bulk cystal substrates (ZnO and MgO), low defect density, easy fabrication, non-toxic and harmless, abundant resources and environmental friendly, which makes them become one of the candidates for ultraviolet (UV) photodetecting. Low dark current and high responsivity are always expected in ZnMgO UV photodetectors. Wurtzite ZnMgO (w-ZMO) UV photodetectors usually show relatively high responsivity, while the dark current is also high. Cubic ZnMgO (c-ZMO) UV photodetectors usually have relatively low dark current, while the responsivity is also low. It is anticipated that mixed-phase ZnMgO (m-ZMO) UV photodetectors have both advantages mentiond in w-ZMO and c-ZMO UV photodetectors. Currently, the responsivity of m-ZMO UV photodetectors is usually high, while the dark current remains high. More importantly, the devices have dual detecting bands and uncontrollable cut-off wavelength due to the films possessing two distinct absorption edges. These problems limit the deeper development of m-ZMO UV photodetectors. For the problem of dual detecting bands and high dark current in m-ZMO UV photodetectors, detailed researches have been done and some breakthrough results were achieved in this thesis. The main contents were as follows: (1) For the problem of the m-ZMO having two distinct absorption edges, m-ZMO thin films with single absorption edge were realized on a-Al2O3 by MBE, whose lattice-mismatch is very small with both ZnO and MgO, and their absorption edges were tuned from 3.9 eV to 4.8 eV. (2) Metal-semiconductor-metal (MSM) structured m-ZMO UV photodetectors were fabricated on m-ZMO thin films with the single absorption band and tunable absorption edge by photolithography and a wet etching procedure and their cut-off wavelength were tuned from 325 nm to 275 nm. The devices have relatively low dark current (40 V, the dark current is 8 pA ~ 130 pA) and high responsivity (40 V, the peak responsivity is 9 A/W ~ 410 A/W). Moreover, the rejection ratio of UV and visual is 103 and the response time is about 37 ms ~ 1 s. It is related with inherently high-resistance c-ZMO and large amounts of heterojuntion grain boundaries between w-ZMO and c-ZMO that the devices have relatively low dark current. It is related with large amounts of heterojuntion grain boundaries between w-ZMO and c-ZMO and deep defects in thin films acting as the traps of holes and prolonging the lifetime of holes that the devices have relatively high responsivity. (3) Our m-ZMO devices have better comprehensive properties from the comparision of related performances of other single-phase and mixed-phase ZMO UV photodetectors, namely, relatively low dark current, relatively high responsivity, relatively high rejection ratio and relatively fast response time. The achievement of high-performance m-ZMO device will have huge directive significance for its development and application o in UV detecting region.
公开日期	2015-12-24
内容类型	学位论文
源URL	[http://ir.ciomp.ac.cn/handle/181722/48836]
专题	长春光学精密机械与物理研究所_中科院长春光机所知识产出
推荐引用方式 GB/T 7714	范明明. 具有单一吸收边的混相ZnMgO薄膜及其紫外探测器件的制备和特性研究[D]. 中国科学院大学. 2015.

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