论文部分内容阅读
采用化学溶液法在氧化铟锡(ITO)衬底上合成ZnO纳米棒,以不同的速度将无定形SiO2材料旋涂于ZnO纳米棒,制备了结构为ITO/ZnO/ZnO纳米棒/SiO2/Al全无机电致发光器件。借助能谱(EDS)和吸收光谱,发现当转速从3000r/min降低到500r/min时,SiO2的附着量逐渐增多。比较了旋涂速度对器件的电致发光光谱的影响,发现对于同一旋涂速度形成的器件,紫外发光强度随电压的增大而增强,可见区的发射则逐渐减弱;而不同旋涂速度下获得的器件的紫外发光强度显示出随电压升高先增大后减小的趋势,当旋涂速度为1000r/min时,紫外发射最强,可见区发光几乎消失;I-V曲线测量显示随着转速的降低,器件的启亮电压变大,最大工作电流逐渐变小。结合光致发光(PL)图谱和能级结构图分析认为,SiO2除了能钝化ZnO纳米棒表面缺陷,还具有改善载流子在发光层的平衡和增大电子注入能量的作用,其较高的势垒对发光层内的电子具有限制作用,提高了在活性层中的电子和空穴的复合率。此外,SiO2的加速作用也有助于提高高能态缺陷能级的电子密度及复合几率。
ZnO nanorods were synthesized by chemical solution method on indium tin oxide (ITO) substrates. The amorphous nanostructures were spin-coated on ZnO nanorods at different rates. ITO / ZnO / ZnO nanorods / SiO2 / Al All inorganic electroluminescent devices. By means of EDS and absorption spectra, it was found that the deposition rate of SiO2 increased gradually when the rotating speed was reduced from 3000r / min to 500r / min. The effects of spin-coating speed on the electroluminescence spectra of the devices were compared. It was found that for the devices formed at the same spin speed, the UV emission intensity increased with the increase of voltage and the emission in the visible region gradually decreased. At different spin-coating speeds When the spin speed is 1000r / min, the UV emission intensity is the strongest, and the light emission in the area is almost disappeared. The IV curve measurement shows that with the decrease of the rotation speed, the UV emission intensity of the obtained device shows a trend of increasing first and then decreasing with the voltage increase. , The turn-on voltage of the device becomes larger, the maximum operating current gradually becomes smaller. Combined with photoluminescence (PL) spectra and energy level structure analysis, it is found that SiO2 not only passivates surface defects of ZnO nanorods, but also has the effect of improving carrier balance in the light-emitting layer and increasing electron injection energy. The potential barrier limits the electrons in the emissive layer and improves the recombination rate of electrons and holes in the active layer. In addition, the accelerating effect of SiO2 also helps to increase the electron density and recombination probability of high energy level defects.