N掺杂p型ZnO材料的制备及其光电性能研究

发布时间：2018-06-03 13:06

  本文选题：Zn_3N_2前驱体 + 反应磁控溅射　； 参考：《电子科技大学》2017年硕士论文

【摘要】：ZnO(氧化锌)是一种新型的在光电探测领域具有很大潜力的直接带隙半导体材料,禁带宽度为3.37eV,计算可知其对应波长在近紫外区域,可见光波段透明。具有抗辐射性能优秀、热稳定性能好、无毒无污染、原料丰富、禁带宽度可调等诸多优点,目前来说,虽然国际范围内的研究者们已经通过P-MBE(等离子辅助分子束外延)、PLD(激光脉冲沉积)等技术制备了性能较好的ZnO紫外光电器件,但仍存在一些需要更加深入研究的问题,例如p型导电的机理、稳定且具有较高空穴浓度和迁移率p型薄膜的制备工艺、掺杂技术等深入研究。本文采用“两步法”来制备氮掺杂的氧化锌薄膜,首先利用射频反应磁控溅射技术,以Zn为靶材,N2为反应气体,在石英衬底上沉积Zn3N2(氮化锌)薄膜,接着在管式炉中高温氧化,将Zn3N2转变为ZnO,通过控制氧化的进程来达到制备ZnO:N的目的。这种方法工艺较为简单,并且在一定程度上提高了N的固溶度。我们研究了射频反应磁控溅射中,氮氩分压、溅射功率和衬底温度对Zn3N2薄膜沉积的影响。得出结论,在氮氩分压为2:1、溅射功率80W、衬底温度200℃条件下能制备出形貌较好,成膜均匀的Zn3N2薄膜。接着将Zn3N2薄膜放入管式炉中,在不同温度下氧化使其转变为ZnO:N,我们利用SEM(扫描电子显微镜)、XRD(X射线衍射)、UV-Vis(紫外-可见分光光度法)等技术手段对ZnO:N薄膜进行表征,得出结论,在氧化温度为700℃、氧化时间3小时的条件下,ZnO:N薄膜呈良好的c轴择优取向生长,晶体中缺陷较少,可见光波段透射率在90%,而在紫外波段具有强烈的吸收,拟合计算得出其光学禁带宽度约为3.55eV。空穴浓度为1.6×1015cm-3,迁移率为0.3cm2/Vs。最后通过在ZnO:N薄膜上溅射Cu叉指电极将其制备成MSM结构的紫外光电导探测器,600℃退火后通过I-V测试表明金属和薄膜形成了较好的欧姆接触。器件暗电流为13.4mA,以254nm的紫外汞灯为光源,测得其光电流为32.2mA,光暗电流比约为2.4,说明薄膜对紫外光有一定的探测性能。
[Abstract]:ZnO (zinc oxide) is a new type of direct bandgap semiconductor material with great potential in the field of photoelectric detection. The band gap width is 3.37 EV. The corresponding wavelength is in the near ultraviolet region and the visible wavelength is transparent. It has many advantages, such as excellent radiation resistance, good thermal stability, non-toxic and pollution-free, abundant raw materials, adjustable bandgap and so on. Although researchers at the international level have prepared ZnO ultraviolet photovoltaic devices with better performance by plasma assisted molecular beam epitaxy (PLD) and other technologies, there are still some problems that need to be further studied. For example, the mechanism of p-type conduction, the preparation process of p-type films with stable and high hole concentration and mobility, the doping technology, etc. In this paper, nitrogen-doped zinc oxide thin films were prepared by "two-step method". Firstly, Zn _ 3N _ 2 (Zn _ 3N _ 2) thin films were deposited on quartz substrates by RF reactive magnetron sputtering (RF reactive magnetron sputtering) and then oxidized at high temperature in tube furnaces, and Zn _ 3N _ 2 (Zn _ 3N _ 2) thin films were deposited on quartz substrates. Zn3N2 was transformed into ZnO and ZnO:N was prepared by controlling the oxidation process. This method is simple and improves the solubility of N to some extent. The effects of partial pressure of argon nitrogen, sputtering power and substrate temperature on the deposition of Zn3N2 thin films have been investigated in RF reactive magnetron sputtering. It is concluded that Zn3N2 thin films with good morphology and uniform film formation can be prepared under the conditions of nitrogen argon partial pressure of 2: 1, sputtering power of 80 W and substrate temperature of 200 鈩，

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