【作者】 赵旺；

【导师】 杜国同；

【作者基本信息】 吉林大学 ， 微电子学与固体电子学， 2011， 博士

【摘要】 氧化锌材料是一种直接带隙宽禁带半导体材料,其在固体照明、信息存储以及显示领域具有巨大的应用潜力。然而,高质量、稳定、可重复的p-ZnO薄膜的制备一直存在较大困难,使得ZnO基高效率紫外发光器件的研究进展缓慢。本论文采用MOCVD技术,围绕高质量ZnO薄膜的制备、ZnO的p型掺杂和ZnO基同质结、异质结发光二极管的制备等方面开展了相关的一系列工作。同时,在制备ZnO薄膜晶体管方面也进行了初步的研究。本论文首先采用MOCVD生长技术在c面蓝宝石、GaN/Al2O3衬底上制备了ZnO薄膜,采用多种测试手段对制备的ZnO薄膜进行了表征分析,重点研究了生长温度以及锌氧比对薄膜结晶质量、形貌以及发光质量等方面的影响。通过实验得到了获得较高质量ZnO薄膜相对优化的生长条件。其次介绍了针对两种v族元素As和P的不同掺杂方法。对于As元素,采用了GaAs夹层的掺杂技术,通过热扩散工艺制备了As掺杂的p型ZnO薄膜。对于P元素,采用了升华的方法,制备出P掺杂的p-ZnO。通过优化生长条件,得到了载流子浓度在1017cm-3量级的p-ZnO薄膜。以前面As掺杂制备p型ZnO的研究为基础,在ITO玻璃衬底上制备出具有紫外电致发光特性的ZnO同质结LED；以P掺杂制备p型ZnO的研究为基础,在n-GaN/Al2O3衬底上制备了p-ZnO:P/n-GaN异质结构的ZnO基发光器件。此外,还在ITO玻璃衬底上制备了基于MIS结构的发光器件。三种器件结构均表现出明显的整流特性,实现了室温下的电致发光。其中,p-ZnO:P/n-GaN异质结构ZnO基发光器件,实现了室温电泵浦紫外光激射。最后,采用MOCVD方法在ITO玻璃衬底表面制备了以MgO为绝缘介质的ZnO薄膜晶体管,优化后器件的开关比达到了105量级。更多还原

【Abstract】 As an II-VI group semiconductor, ZnO has attracted great interest for its wide band gap (3.37eV) and relatively large exciton binding energy (60meV) at room temperature. It has been regarded as one of the most promising candidates for the next generation of ultraviolet (UV) light-emitting diode (LED) and lasing diode (LD) operating at high temperatures and in hard environments.However, after years of research, the progress of ZnO-based light-emitting devices is very slow. One key problem is the lack of device-quality ZnO films, especially the stable and reproducible p-type ZnO films.In this thesis, many research works are conducted to fabricae high quality native ZnO films, p-ZnO films, ZnO-based homojunction and heterofunction short wavelength light-emitting devices. ZnO films and p-type doping of ZnO thin films are grown on many kinds of substrates by Metal-Organic Chemical Vapor Deposition (MOCVD) technique, and the effects of growth conditions on the structural, surface morphology and optical properties of the deposited ZnO films have been investigated.ZnO films are grown by MOCVD on c-plane sapphire and GaN/Al2O3 substrates. The effects of the growth temperature and source gas flow ratios on the properties of the films are analysed and the range of optimized growth conditions are obtained.MIS structure of light-emitting devices is fabricated on ITO-glass substrate by MOCVD, and the material of insulating layer is MgO. The turn-on voltage is about 2V and the reverse breakdown voltage higher than -6 V. Ultraviolet (Center wavelength 379nm) electroluminescence (EL) from ZnO layer are observed under forward bias at room temperature (RT).The p-type ZnO:As layer is formed using GaAs interlayer as the As precursor. The GaAs interlayer was pre-deposited on ITO substrate by sputtering method. The thickness of GaAs interlayer is the key to fabricate the p-ZnO films. When the thickness of GaAs interlayer is 20nm, the electrical properties of As-doped p-ZnO films show hole concentration of 1017/cm3. Based on the p-ZnO:As film, ZnO homojunction LED with is fabricated on ITO-glass by MOCVD. The device exhibits desirable rectifying behaviour. Ultraviolet and visible light electroluminescence are observed from ZnO homojunction device under forward bias at room temperature.P-doped ZnO films (p-ZnO:P) are grown by MOCVD techniques, and sublimate the red phosphorus as the doping source.On this basis, p-ZnO:P/n-GaN heterojunction light-emitting device is fabricated on n-GaN substrate by MOCVD.The device exhibits desirable rectifying behaviour. The electrical pump UV lasing (Centred at 375nm)is detected from this device at room temperature, and the threshold current density is only 1.2A/cm2.ZnO transparent thin-film transistors with MgO as a gate dielectric were fabricated on ITO substrate by all MOCVD technology. The drain current can be modulated by the voltage of gate. Experiment results show that the ZnO-TFTs operate in n-channel mode with an on/off ratio about 105.更多还原