排序方式: 共有17条查询结果,搜索用时 15 毫秒
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采用溶胶-凝胶法在石英玻璃衬底上制备了Al/Zn原子比为0.1%的ZnO:Al薄膜,在500℃的氩气中进行了1~5h不同时间退火处理,利用X射线衍射(XRD)、光致发光(PL)、透射光谱和四探针法研究了退火时间对薄膜性能的影响。结果显示,退火1h时,样品出现了C轴择优取向,深能级发射(DLE)提高,可见光区光学透过率约为80%,电阻率仅为4×10^-2Ω·cm。更长时间退火后,随着退火时间增加,薄膜结晶质量逐渐变差,电阻率逐渐增大。 相似文献
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模拟研究常闭和常开工作模式下的平面栅极型碳纳米管场发射电子源 总被引:1,自引:1,他引:0
采用数值模拟的方法对比性地研究了常闭和常开工作模式下平面栅极型碳纳米管场发射电子源.静电场的数值计算结果显示:常闭工作模式下该电子源中阴极电极的表面电场分布不均匀,边缘处的高电场易导致其上的碳纳米管烧毁,从而引起场发射电流衰减.为了解决此问题,提出将常开工作模式用于该电子源,并证实常开工作模式能够用于该电子源,并有利于解决电流衰减问题.因此,相对于常闭工作模式,常开工作模式更适合平面栅极型碳纳米管场发射电子源. 相似文献
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由于碳钢材料在许多领域有着非常广泛的应用,所以研究碳钢的无损探伤规律具有很重要的现实意义。为探究碳钢在脉冲红外热成像无损探伤中的规律,特设计A、B两种标准试件,利用脉冲红外热成像技术对两种标准碳钢试件中缺陷的大小和深度进行了定量化研究。研究结果表明,测量近表(l〈1.8mm)小缺陷的大小时,应选择在热脉冲作用后约0.3s进行,此时测量误差比较小,并且对深度小的缺陷进行大小的测量要比深度较大的缺陷困难。对于深度较大的缺陷.只要红外热图像清晰,测量误差都比较小。测量缺陷深度时,当缺陷直径大于6mm时,测量误差比较小。当缺陷直径小于6mm时,误差比较大,甚至无法探测到缺陷。由于热扩散,测量缺陷的深度应选择在热脉冲作用后的短时间内进行,以保证红外热图像的清晰度,减小测量误差。 相似文献
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ZnS:Na thin films with (111) preferred orientation were deposited on glass substrates by vacuum evaporation method. The as-prepared films were annealed in flowing argon at 400--500 ℃ to improve the film crystallinity and electrically activate the dopants. The structural, optical and electrical properties of ZnS:Na films are investigated by X-ray diffrac- tion (XRD), photoluminescence (PL), optical transmittance measurements and the four-point probe method. Results show that the as-prepared ZnS:Na films are amorphous, and exhibit (111) preferred orientation after annealing at 400 --500 ℃. The PL emissions at 414 nm and 439 nm are enhanced due to the increase of the intrinsic defects induced by the thermal annealing. However, all the samoles exhibit high resistivitv due to the heavy self-compensation. 相似文献
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尼龙材料内部缺陷的红外热成象无损检测 总被引:3,自引:1,他引:3
介绍了利用脉冲式加热的红外热成象无损检测技术定量检测尼龙材料内部缺陷大小及深度的方法,并给出了实验结果及分析。 相似文献
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The feasibility of a new fabrication route for N and Ga codoped p-type ZnO thin films on glass substrates, consisting of DC sputtering deposition of Zn3N2:Ga precursors followed by in situ oxidation in high purity oxygen, has been studied. The effects of oxidation temperature on the structural, optical and electrical properties of the samples were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), optical transmittance and Hall effect measurements. The results were compared to a control film without Ga. XRD analyses revealed that the Zn3N2 films entirely transformed into ZnO films after annealing Zn3N2 films in oxygen over 500 ℃ for 2 h. Hall effect measurements confirmed p-type conduction in N and Ga codoped ZnO films with a low resistivity of 19.8 Ω?cm, a high hole concentration of 4.6E18 cm3 and a Hall mobility of 0.7 cm2/(V s). These results demonstrate a promising approach to fabricate low resistivity p-type ZnO with high hole concentration. 相似文献