【作者】 万文坚；

【导师】 姚若河；

【作者基本信息】 华南理工大学 ， 微电子学与固体电子学， 2011， 硕士

【摘要】 本文采用连续离子层吸附与反应法（SILAR）制备Al掺杂ZnO薄膜,研究掺杂浓度及退火处理对薄膜结晶性能的影响;两步法化学浴沉积（CBD）制备ZnO柱状多晶薄膜,研究不同种子层数以及不同Al掺杂浓度种子层对ZnO柱状阵列薄膜的影响;SILAR制备薄膜型ZnO/CuSCN异质结,研究异质结的电学特性;CBD制备ZnO柱状阵列薄膜和SILAR制备CuSCN薄膜构成柱状异质结,研究异质结的电学特性。结果表明:SILAR制备ZnO具有c轴择优取向性,结晶性好,薄膜由31.3nm的晶粒聚集成的长约1μm的大颗粒组成,颗粒呈长楔形状,薄膜表面粗糙,均匀性差;铝掺杂后c轴择优取向性变差,晶粒尺寸随掺杂浓度的增加而增大,颗粒呈球状,尺寸变小,薄膜表面均匀平整。掺杂浓度为2%的薄膜表面最平整,颗粒最小,直径约200nm。退火处理减弱c轴择优取向性,晶粒尺寸变大,晶格常数更接近于标准。CBD制备ZnO柱状多晶薄膜结晶性良好,有较强的（002）择优取向性,晶格常数a=3.249（?）,c=5.207（?）。薄膜由柱状ZnO晶体竖向排列而成,直径约500nm。随着种子层沉积次数的增加, ZnO柱状阵列越来越密集。种子层为40次时,ZnO柱状晶体连在一起,薄膜片状生长。种子层掺铝后生长的ZnO柱状晶体排列致密,大小均匀一致,直径约300nm。2%掺杂种子层上制得的柱状阵列薄膜最均匀,表面最平整。薄膜型ZnO/CuSCN异质结,XRD表征薄膜分别为纤锌矿ZnO和（?）-CuSCN。形貌表征ZnO多晶颗粒呈球状,大小约300nm,CuSCN多晶颗粒呈片状,大小约2μm。电学表征异质结具有明显的整流特性,±4V时整流比为47.0,饱和电流密度Js=9.94×10^-8A/cm²,二极管理想因子n=4.61,缺陷辅助隧穿为主要电流输运机制,在(0.4V²V,I-V特性受陷阱辅助空间电荷限制电流（SCLC）机制影响,I∝V^3.4。柱状阵列ZnO/CuSCN异质结,XRD表征薄膜分别为纤锌矿ZnO和（?）-CuSCN,ZnO的结晶性优良,具有明显的（002）择优取向性。形貌表征分析ZnO呈柱状晶体竖向致密排列,直径约1μm,CuSCN为片状多晶交织排列,大小约3μm。电学表征异质结具有良好的整流特性,±3V时整流比为48.3。电压从小至大电流传输特性分别由缺陷和界面态的复合、缺陷辅助隧穿、陷阱辅助空间电荷限制电流决定。柱状阵列ZnO/CuSCN异质结比薄膜型异质结的整流比、电流密度、二极管区域范围都大,电学性能更好。更多还原

【Abstract】 This paper, Al-doped ZnO thin films were grown by successive ionic layer adsorption and reaction (SILAR) method, the effects of doping concentration and annealing were studied; Columnar array polycrystalline ZnO films were deposited by a two-step chemical bath deposition (CBD), the influences of different seed layers and different doping concentration of Al-doped ZnO seed layer were studied; Thin films ZnO/CuSCN heterojunction was prepared by SILAR, columnar array ZnO/CuSCN heterojunction was constituded by CBD-deposited rod array ZnO films and SILAR-deposited CuSCN thin films, both electrical properties had been Analysized. The results showed that:ZnO thin films grown by SILAR, were oriented along (002) with hexagonal phase, were composed of wedge-shaped clusters with size about 1μm. Doping by Al made c-axis orientation became lower, clusters’shape became spherical, and the surface became smoother. When doping to 2%, the films became the most compact and uniform. Annealing treatment can promote crystallized, simultaneously reduce ZnO thin films’c-axis orientation.Columnar array ZnO films showed excellently crystallization with highly (002) oriented growth. The films were composed by columnar ZnO crystals vertical to the substrate with diameter of 500nm. The greater the number of seed layer deposition was, the more compact films were. Films covering on Al-doped ZnO seed layer were more compact and uniform, When doping concentration was 2%, the films had the most uniform and smooth surface.Thin films ZnO/CuSCN heterojunction showed ZnO was wurtzite with spherical clusters and CuSCN was (?)-phase. The heterojunction showed a good rectifying behavior with a rectification ratio of 47.0 at±4V. The current transport mechanism was dominated by trap-assisted tunneling at low forward bias voltages and by the trap-assisted space-charge limited current (SCLC) conduction at higher forward bias voltages.Columnar array ZnO/CuSCN heterojunction was composed of excellently crystallized ZnO with columnar shape and (?)-CuCSN with sheet shape. The heterojunction had a rectification ratio of 48.3 at±3V. The current transport mechanism was dominated by the recombination and trap-assisted tunneling at low forward bias voltages and by SCLC conduction at higher forward bias voltages. Compared to thin films heterojunction, the columnar array one had better electrical properties.更多还原