【作者】 李超群；

【导师】 申德振； 张振中；

【作者基本信息】 中国科学院研究生院(长春光学精密机械与物理研究所) ， 凝聚态物理， 2014， 博士

【摘要】 200-300nm的深紫外区的半导体光电探测器因其广泛应用而备受关注，而以宽禁带半导体材料ZnO（MgZnO）为基础的紫外探测器是其中一个研究热点。本文通过对MgZnO薄膜的掺杂的研究，实现了新型垂直结构器件的制备和对MgZnO薄膜电学性能的优化；还对Ga2O3/ZnO异质结构紫外探测器进行了制备与研究，内容如下：1、利用磁控溅射的方法生长出了Al掺杂的MgZnO薄膜，并通过不同温度退火处理将薄膜电阻率降至最低至4.7E-3ohmcm，高导电率的MgZnO：Al薄膜为制备垂直结构探测器提供了必须的透明电极，通过扫描电镜图像、紫外吸收透射谱等测试证明该MgZnO：Al薄膜适用于本文设计的垂直结构紫外探测器；在MgZnO：Al透明电极上生长MgZnO反应层并在其上接触Au电极形成肖特基接触，完成垂直结构肖特基势垒光电二极管的制备；对制备的新型器件进行了光电参数测量和紫外光响应特性的研究，器件具有良好的肖特基整流特性和0V偏压下的响应。2、利用金属化学气相沉积方法(MOCVD)进行了不同组分Ga掺入立方相MgZnO薄膜的制备。通过X射线衍射谱、X射线光电子能谱、扫描电镜图像、吸收光谱等测试的结果讨论了不同组分Ga的掺入对MgZnO薄膜晶体结构和性质的影响，发现随着Ga掺入浓度的提高，立方相MgZnO薄膜出现了分相。对未分相MgZnO:Ga薄膜的电学性能进行测试，研究Ga掺入对MgZnO薄膜电学性能的影响，制备MSM结构紫外探测器并对器件性能进行测试与研究。3、利用MOCVD在蓝宝石衬底上在获得了高质量Ga2O3薄膜，并在Ga2O3薄膜上生长薄层ZnO实现Ga2O3/ZnO异质结的制备。Zn的热扩散，实现了Ga2O3的弱p型掺杂，为Ga2O3/ZnO异质p-n结探测器件的制备奠定了基础。更多还原

【Abstract】 Ultraviolet is weak in the atmosphere and for its short propagation length,multiplication effect is necessary in ultraviolet photodetector. Schottky junction is agood choice for high performance ultraviolet photodetectors. It works based on thebarrier between the metal and semiconductor as they are connected. So it’s easilyinfluenced by the surface state of the active layer of the device. As an important wideband gap semiconductor, zinc oxide has been investigated in many forms, amongwhich MgZnO alloy is believed to be the most efficient candidate for deepultraviolet photoelectronic device due to its large tunable band gap. MgZnO has beenextensively studied for its optics and electricity properties based on its wideapplications as photodetector. A part of the studies were focused on the nanosizedMgZnO with the purpose of improving the light absorption, therefore another partfocused on the quantum well structures to reduce the internal field in order to increasethe internal efficiency:1. We report on a Schottky ultraviolet photodetector with a MgZnO: Altransparent electrode. By using doping and post annealing, transparent conductiveMgZnO:Al thin films was developed to fit the request for our detection. The deviceis structured vertically in an order of sapphire/MgZnO: Al/as-grown MgZnO/Au.The device shows a good Schottky contacting character. The peak response is located at340nm and cut-off at355nm. The turn-on voltage is2.0V and thebreakdown voltage is40V. The leakage current is less than70pA at a reverse biasof15V.2. The metal-organic chemical vapor deposition method was successfully usedto synthesize pure MgZnO and Ga doping MgZnO. The flow rate of TEGa waschanged to study how the dopant-Ga affect the structure of MgZnO. The MgZnOstructure was verified with x-ray diffraction, which showed typical characteristicsphalerite reflections without any separate dopant-related peaks.. X-ray diffractionalso demonstrate that along with the growth of Ga dopant in number. ZnGa2O4isturned up in the film which made the MgZnO phase split. Scanning electronmicroscopy observations confirmed the existence of homogeneously distributedhexagonal crystal and cubic crystal and a little rhombus crystal.更多还原