【作者】 倪佳苗；

【导师】 赵修建；

【作者基本信息】 武汉理工大学 ， 建筑材料与工程， 2010， 博士

【摘要】 透明导电氧化物(TCO)薄膜的p型掺杂是目前半导体材料领域研究热点之一,缺乏光电性能良好的p型TCO薄膜严重阻碍了透明电子器件的发展。本论文报告具有优异光电特性的p-SnO2透明导电薄膜及其相应的SnO2基同质和异质结的制备、结构与性能。主要结果与创新点如下：(1)在石英玻璃上制备了SnO2：Sb(ATO)薄膜并研究了热处理温度对导电类型和性能的影响。热处理温度对n、p型转化有很大影响,温度太低Sb难以进入Sn的取代位,温度过高导致5价Sb的形成,973K为最佳,空穴浓度最高达到5.83×1019cm-3,薄膜晶化度较高；可见光透过率达80%以上。(2)在单晶硅上制备了SnO2：Sb薄膜并研究了基片温度对其导电类型和性能的影响。基片温度显著影响n、p型转化和p型导电的性能。随着基片温度升高,薄膜中颗粒形状由圆球形到类似锥形体,再变成类似纳米棒,晶格更完整和有规律,减少了晶界散射,形成性能优异的p型导电薄膜。523K时,薄膜p型导电性能最佳,空穴浓度高达1.64×1020cm-3,迁移率达8.33cm2V-1s-1；薄膜晶化程度最高,晶粒呈纳米棒状,直径约为50nm,并且沿着(101)面方向生长。(3)在石英玻璃基片上沉积Sn02：Zn薄膜或三明治结构的Zn/SnO2/Zn薄膜,再经高温热处理或热扩散处理,制得p型Sn02：Zn透明导电薄膜,可见光透过率可达80%以上。但由于Zn2+属于深能级掺杂,电学性能比p型SnO2：Sb薄膜差得多。(4)将p型SnO2薄膜结合n型和本征材料,制备了对应p-n或p-i-n同质结或异质结。单晶硅上p-n结(p-ATO/n-ATO同质结)和p-i-n结(p-ATO/i-SnO2/n-ATO与p-ATO/i-ZnO/n-ATO异质结)具有很好的整流特性,漏电流很小,反向电压很大,开路电压大于3V；石英玻璃上沉积的p-n结(p-ATO/n-ATO和p-SnO2：Zn/n-ATO)也具有整流的I-V曲线特性,但存在较小的漏电流,反向电压较小,开路电压小于3V,紫外可见光范围的平均透过率达到85%,实现了真正透明的p-n结器件。更多还原

【Abstract】 As transparent conductive oxide (TCO) thin films, p-type doped semiconductor material is widely researched in recent years, lack of good p-TCO thin films in optoelectronic properties is the main problem for its application in electronic devices. This dissertation presents the preparation, structure and properties of a new type transparent p-SnO2 thin films and SnO2-based homogeneous and heterogeneous junction which have good photo-electrical performances. The main results and conclusions are as follows.(1) Sb-doped SnO2 (ATO) thin films were deposited on quartz glass substrates and the effects of annealing temperature on p-type conducting and performance were discussed. The results indicated that the annealing temperature was critical to prepare such p-type conducting ATO films. It was found that 973K is the optimum annealing temperature to get p-ATO films with highest hole concentration (5.83×1019cm-3). If the temperature is too low, it is difficult that Sn ion is replaced by Sb; whereas Sb3+ is oxidized to Sb5+ under high temperature. In addition, the average transmittance of films in visible region is high as 80%.(2) Sb-doped SnO2 thin films were deposited on single crystal silicon substrate and the effects of substrate temperature on p-type conducting and performance were studied. The results indicated that substrate temperature was critical to prepare p-ATO films. As the substrate temperature increases, the nano-particles in the films change their morphology from sphere-type to cone-like, and last to nanorod-array-like, the lattice of crystals becomes perfect, which decreases the grain boundary scattering and results in good performance of p-type conducting. It was found that 523K is the optimum substrate temperature to get p-ATO films with highest hole concentration (1.64×1020cm-3) and mobility (8.33cm2V-1s-1). At 523K, the thin-films are highly crystallized with nanorod-array-like structure, optimum grain size (about 50 nm in radius of the rods) and (101) plane orientation.(3) p-type SnO2:Zn thin films were prepared by depositing Zn-doped SnO2 thin films or sandwich structure Zn/SnO2/Zn films on quartz glass substrates following heating-treatment or thermal diffusion process, and their visible light transmittance is higher than 80%. However, p-type conductivity is much smaller than thsoe of SnO2:Sb thin films, due to Zn doping in SnO2 belongs to deep-level doping.(4) p-n and p-i-n homojunctions or heterojunctions were assembled using the above prepared p-SnO2 and other n-type and intrinsic materials. The results show that p-n (p-ATO/n-ATO) and p-i-n (p-ATO/i-SnO2/n-ATO and p-ATO/i-ZnO/n-ATO) homojunctions or heterojunctions deposited on single crystal Si substrate have very good rectification properties, small leakage currents, large backward breakdown voltages and open circuit voltages of>3V; the pn junctions (p-ATO/n-ATO and p-SnO2:Zn/n-ATO) deposited on the quartz glass substrates have also the rectification characteristics in IV curves, with small leakage currents, smaller backward breakdown voltages and open-circuit voltage smaller than 3V. The pn junctions on quartz glass substrates are transparent in all the visible region and the average transmittance of 85% was achieved.更多还原