具有微米/纳米复合粗化ITO的GaN基LED

Three types of textured indium-tin-oxide （ITO） surface, including nano-texturing and hybrid micro/nano-texturing with micro-holes （concave-hybrid-pattem） or micro-pillars （convex-hybrid-pattern）, were applied to GaN-based light-emitting diodes （LEDs）. The nano-texturing was realized by maskless wet-etching, and the micro-texturing was achieved by standard photolithography and wet-etching. Compared to LED chips with flat ITO surface, those with nano-pattern, concave-hybrid-pattern, and convex-hybrid-pattern exhibit enhancement of 11.3%, 15.8%, and 17.9%, respectively, for the light-output powers at 20 mA. The electrical performance has no degradation. Moreover, the convex-hybrid-pattern show higher light-output efficiency under small injection current, while the concave-hybrid-pattern exhibit better light-output efficiency at large injection current. The light- extraction efficiency is simulated by use of two-dimensional finite difference time domain method, and the numer- ical results are consistent with the experiments.     

薄膜晶体管透明电极铟锡氧化物雾状不良的分析研究

对FFS-TFT制作工艺中,与氮化硅膜层接触的透明电极ITO发生的雾状不良进行分析研究。通过扫描电子显微镜、宏观/微观显微镜和背光源测试设备对样品进行分析。结果显示接触层的等离子体界面处理对ITO的透过率和膜质特性有较大影响,可导致严重的雾状不良发生和刻蚀工艺中的膜层下端过度刻蚀的问题。通过在透明电极ITO上面沉积微薄的过渡缓冲膜层,并优化界面等离子体处理条件,可以改善雾状不良。     

Study of schottky barrier heights of indium-tin-oxide on p-GaN using x-ray photoelectron spectroscopy and current-voltage measurements

In this study, the current density-voltage (J-V) characteristic of Schottky diodes of indium-tin-oxide (ITO) contacts to p-type GaN (p-GaN) has been investigated. The calculated barrier-height value of ITO/p-GaN samples using the thermionic field-emission (TFE) model is 3.2 eV, which implies that the work function of ITO is equal to 4.3 eV. The result is supported by J-V measurements of ITO/n-type GaN Schottky diodes. On the other hand, the barrier height of ITO/p-GaN was also determined from x-ray photoelectron spectroscopy (XPS) data. The analysis of the XPS spectral shifts indicated that this observed barrier-height value of ITO/p-GaN by XPS is in good agreement with the value of 3.2 eV obtained from J-V measurements.     

Transparent conducting indium-tin-oxide (ITO) film as full front electrode in III-V compound solar cell

The application of transparent conducting indium-tin-oxide (ITO) film as full front electrode replacing the conventional bus-bar metal electrode in III-V compound GaInP solar cell was proposed. A high-quality, non-rectifying contact between ITO and 10 nm N⁺-GaAs contact layer was formed, which is benefiting from a high carrier concentration of the terrilium-doped N⁺-GaAs layer, up to 2×10¹⁹ cm^-3. A good device performance of the GaInP solar cell with the ITO electrode was observed. This result indicates a great potential of transparent conducting films in the future fabrication of larger area flexible III-V solar cell.     

Formation process of indium oxide transparent conducting films via thermal decomposition

Indium 2-ethylhexanoate monohydroxide, In(OH)(O₂CCH(CH₂CH₃)(CH₂)₃CH₃)₂, is a precursory material to fabricate In₂O₃-based transparent conducting films by dip-coating process. Formation process of indium oxide transparent conducting films was investigated using an ultra-low acceleration voltage FE-SEM. The nanostructure change of the precursory layer was observed during the electron beam irradiation in vacuum. A flat and homogeneous surface of the as-coated layer changed to porous and net-work like nanostructure after 80 s; the pore diameter increased and the pore distance decreased although the number of pores remained unchanged. These processes were interpreted as the preliminary step to form porous films composed of nm-sized inter-linked oxide particles as reported in the previous papers by the authors.     

Evolution of water vapor from indium-tin-oxide thin films fabricated by various deposition processes

Tin-doped In₂O₃ (indium-tin-oxide) transparent conducting films are widely used as electrodes of liquid crystal displays and low-E windows. In the present study, a systematic TDS study was undertaken for ITO films fabricated by various deposition processes; such as PVD, dip coating and spray deposition. Water vapor was the main gas evolved from the films; gas evolution from the silicon substrate was negligible. The evolution proceeded via two steps at approximately 373 and 473-623 K. The amount of the evolved water was in the order: (dip-coated film)>(PVD films)> (spray-deposited film). This order was identical to that of the film's resistivities. This revised version was published online in August 2006 with corrections to the Cover Date.     

用表面粗化ITO的欧姆接触提高GaN基LED性能

应用ICP干法刻蚀工艺和自然光刻技术,制备了ITO表面粗化的GaN基LED芯片。聚苯乙烯纳米颗粒在干法刻蚀中作为刻蚀掩膜。通过扫描电镜(SEM)观察ITO薄膜的粗糙度,并且报道了优化的粗化工艺参数。结果表明,ITO表面粗化的GaN基LED芯片同传统的表面光滑的芯片相比在20 mA的驱动电流下,发光强度提高了70%。     

ZnO/TiO2复合涂层电极的制备及其光电性能

以氧化铟锡导电玻璃为基材,采用电泳沉积法制备负载型ZnO/TiO2复合涂层,经450℃后续烧结处理后,采用XRD、SEM、EDX和UV-Vis DRS对ZnO/TiO2复合涂层进行表征;在pH=7.00的磷酸盐缓冲溶液中,分别测试ZnO/TiO2复合涂层电极在紫外灯和100 W白炽灯辐照下的电化学阻抗谱、Tafel极化曲线和循环伏安等电化学性质。结果表明:ZnO以200~300 nm晶粒分散于复合涂层中,质量百分比为0.74%;ZnO/TiO2复合涂层在可见光区有一定的吸收;在可见光辐照下ZnO/TiO2复合涂层电极具有较好的光电活性,并对水的分解具有较强的光电催化活性。     

基于氧化铟锡的无结低电压薄膜晶体管

在室温下制备了基于氧化铟锡(ITO)的底栅结构无结薄膜晶体管. 源漏电极和沟道层都是同样的ITO薄膜材料,没有形成传统的源极结和漏极结, 因而极大的简化了制备流程,降低了工艺成本.使用具有大电容的双电荷层SiO₂作为栅介质, 发现当ITO沟道层的厚度降到约20 nm时, 器件的栅极电压可以很好的调控源漏电流. 这些无结薄膜晶体管具有良好的器件性能: 低工作电压(1.5 V), 小亚阈值摆幅(0.13 V/dec)、 高迁移率(21.56 cm²/V·s)和大开关电流比(1.3× 10⁶). 这些器件即使直接在大气环境中放置4个月, 器件性能也没有明显恶化:亚阈值摆幅保持为0.13 V/dec,迁移率略微下降至18.99 cm²/V·s,开关电流比依然大于10⁶.这种工作电压低、工艺简单、 性能稳定的无结低电压薄膜晶体管非常有希望应用于低能耗便携式电子产品以及新型传感器领域.     

聚乙烯咔唑／铟锡氧化物的界面分析

用原子力显微镜(AFM)和X射线光电子能谱(XPS)研究了真空蒸镀聚乙烯咔唑(PVK)薄膜的表面形貌和PVK／铟锡氧化物(ITO)界面电子状态。结果表明，PVK分子虽然体积较大，但分布较均匀。XPS数据显示，在界面处PVK分子骨架和SnO2分子结构几乎没有发生变化，但PVK分子的侧基和In2O2分子结构发生了变化，因为界面处存在大量的，不能用制备过程的空气污染来解释的C-O键；在界面处，In2O3分子部分分解，所产生O原子替代PVK侧基上的H原子而形成C—O键；所产生的In原子则扩散至PVK内部。