【作者】 张瑞捷；

【导师】 马向阳； 杨德仁；

【作者基本信息】 浙江大学 ， 材料物理与化学， 2010， 硕士

【摘要】 ZnO具有3.37 eV的直接宽禁带,在室温下有相当高的激子束缚能（60 meV）,是潜在的电致紫外发光器件的半导体材料。当ZnO与CdO形成合金半导体Cd_xZnO_1-xO时,禁带宽度可以减小到～1.8 eV,因而可用于制备电致可见发光器件。本文在硅基上制备了基于ZnO缺陷发光的电致发光器件,研究了其发光性能;此外,利用反应磁控溅射法制备了Cd_xZnO_1-xO薄膜,研究了其光致发光随热处理条件的变化情况,为制备基于Cd_xZnO_1-xO薄膜的电致可见发光器件打下基础。本文得到了如下主要结果;以溶胶-凝胶法在重掺硼硅片（p⁺-Si）衬底上制备含有ZnO晶粒的Zn₂SiO₄（Zn₂SiO₄:ZnO）薄膜,形成硅基Zn₂SiO₄:ZnO薄膜发光器件。该器件表现出良好的整流特性;在正向偏压下,器件产生与ZnO缺陷相关的电致发光,发光强度随着正向偏压的增大而不断增强,而反向偏压下器件不发光。基于该器件的能带结构,初步解释了上述载流子输运和电致发光的机理。利用直流反应磁控溅射生长了高度c轴取向生长的单一六方相Cd_xZnO_1-xO薄膜,研究了热处理对薄膜的晶体结构和光致发光的影响。结果表明:（a）经过不同温度（500-800℃）常规热处理,随着热处理温度的升高,Cd_xZnO_1-xO薄膜中Cd含量逐渐降低,且由于Cd的挥发而使薄膜出现孔洞,与此同时薄膜分相,而发光峰位由于薄膜中物相的变化而发生相应的变化。（b）经N₂气氛下500-700℃快速热处理（RTA）后的薄膜的光致发光强度显著提高。随着RTA温度的升高,Cd含量较低的薄膜始终保持单一六方相,近带边辐射发光峰位稍有蓝移;Cd含量较高的薄膜中含Cd的ZnO相与含Zn的CdO相共存,其PL谱中出现与这种物相相关的两个近带边辐射发光峰,且随着温度升高发光峰位蓝移。更多还原

【Abstract】 ZnO possesses a 3.37 eV direct bandgap and a considerably high exciton binding energy of 60 meV at temperature, thus being a promising material for ultraviolet （UV） electroluminescence （EL） devices. When ZnO is alloyed with CdO to be Cd_xZnO_1-xO, its bandgap energy can be as low as～1.8 eV. Therefore, Cd_xZnO_1-xO alloys are expected to be employed in the visible EL devices. In this thesis, EL devices based on ZnO-containing films have been fabricated on silicon substrates, being addressed with their EL performances. Moreover, Cd_xZnO_1-xO films have been prepared by reactive magnetron sputtering. The evolution of their photoluminescence （PL） with the subsequent anneals has been investigated. The primary results in this thesis are listed in the following.The Zn₂SiO₄ films containing ZnO grains （Zn₂SiO₄:ZnO films） were prepared on heavily boron-doped silicon （p⁺-Si） substrates by sol-gel method, thus forming Si-based Zn₂SiO₄:ZnO film light-emitting devices. Such devices exhibit well-defined rectifying characteristics. Under forward bias, the devices generate EL related to the defects in ZnO and, moreover, the EL intensity increases with the forward bias voltage. While, the devices do not exhibit EL under reverse bias. Based on the energy band structure of the devices, we have tentatively explained the mechanisms of the aforementioned electrical transportation and EL.Highly c-axis oriented Cd_xZnO_1-xO films have been prepared by reactive magnetron sputtering. Based on the investigation on the effect of heat treatments on the crystallinity and PL of the films, it has been shown that: （a） After the conventional furnace annealing at 500-800℃, the Cd contents in the films are notably decreased. To be worse, quite a few of voids are formed in the films due to the volatilization of Cd. In the meantime, phase segregation occurs in the films and the PL peaks change notably with the evolution of phases in the films. （b） After the rapid thermal annealing （RTA） at 500-700℃in N₂ ambient, the PL intensities of the films increase significantly. With the increase of RTA temperature, for the low-Cd-content films, they are of single hexagonal phase and the near-band-edge （NBE） emission peak is somewhat blue-shifted. While, for the high-Cd-content films, there are two NBE peaks related to Cd-containing ZnO and Zn-containing CdO respectively in their PL spectra. Moreover, the two NBE peaks are blue-shifted with the increase of RTA temperature.更多还原