同质外延生长ZnO单晶结构及光电性能的研究

本文报道了同质外延生长氧化锌(ZnO)单晶在高温氧气气氛退火前后的结构及光电特性。利用化学气相输运(CVT)法生长了红棕色的ZnO单晶,且进行高温氧气气氛退火处理后的ZnO单晶呈现无色透明状。通过X射线衍射仪(XRD)、X射线光电子能谱(XPS)、能谱仪(EDS)和拉曼(Raman)光谱测试分析了高温氧气气氛退火前后的ZnO单晶结构,讨论了退火对单晶内部缺陷类型及结构的影响。XRD测试表明ZnO单晶的生长方向为(002)方向。退火前后ZnO单晶的ω摇摆曲线半高宽分别为59″和31″,表明退火后单晶内缺陷显著减少;XPS和EDS能谱分析了退火前后ZnO单晶的成分和元素价态,结果表明高温氧气气氛处理后单晶内Zn和O元素含量比更接近理论值;通过Raman光谱分析了高温氧气气氛处理前后ZnO单晶的不同拉曼振动模式;通过紫外光谱数据分析,得到了退火前后ZnO单晶的光学禁带宽度分别为3.05 eV和3.2 eV;最后,通过Hall测试分析了高温氧气气氛退火处理前后ZnO单晶的电学性能参数,并深入讨论了退火前后ZnO单晶的低温电输运特性。

Structure and Photoelectric Properties of ZnO Single Crystal Grown by Homoepitaxy

The structure and photoelectric properties of ZnO single crystal grown by homoepitaxy before and after annealing was reported. The red-brown ZnO single crystals were grown by the chemical vapor transport (CVT) method. The ZnO single crystal annealed in a high-temperature oxygen atmosphere shows colorless and transparent. The structure of the ZnO single crystal before and after annealing was analyzed by XRD, XPS, EDS, and Raman. The effect of annealing on the defect type and structure of a single crystal was discussed. XRD results show that the growth direction of the ZnO single crystal is (002). The FWHM of ω-rocking curve of ZnO single crystal before and after annealing is 59″ and 31″, respectively. It indicates that the defects in the single crystal decrease significantly after annealing. The composition and valence of elements in the single crystal before and after annealing were analyzed by XPS and EDS, and the results show that the content ratio of Zn and O elements in the single crystal after high-temperature oxygen atmosphere treatment is closer to the theoretical value. Raman spectroscopy analyzed the high-temperature oxygen atmosphere. The different Raman vibration modes of ZnO single crystal before and after annealing were analyzed. Through UV spectrum data analysis, the optical band-gap of ZnO single crystal before and after annealing is obtained to be 3.05 eV and 3.2 eV, respectively. Finally, the ZnO single crystal’s electrical properties before and after annealing in a high-temperature oxygen atmosphere were analyzed by Hall test. The low-temperature electrical transport characteristics of ZnO single crystal before and after annealing were discussed in depth.