利用紫外透射光谱研究透射式GaN光电阴极的材料结构及光学特性

GaN紫外光电阴极是近年发展起来的一种高性能真空紫外探测器件,其中透射式结构作为光电阴极实际应用的工作模式,其多层结构参数及光学特性对阴极的最终光电发射性能有着重要的影响.测试了透射式GaN阴极材料的紫外透射光谱,通过建立透射式GaN阴极样品的透射模型,得到了GaN阴极样品的薄膜厚度、光学吸收系数与透射谱之间的函数关系.计算得到的GaN外延材料的厚度与实际值误差小,吸收系数与已发表数据一致,表明紫外透射光谱法能够准确地实现透射式GaN阴极材料结构及光学特性的评估.

Investigation of material structure and optical property of transmission-mode GaN photocathode by ultraviolet transmission spectral

GaN UV photocathode has become a high-performance vacuum ultraviolet detectors in recent years. As the photocathode practical application mode, transmission-type multilayer structure and its optical property have important influences on photocathode photoemission performance. Ultraviolet transmission spectra of transmission-mode GaN photocathode were measured. The optical transmission model of transmission-mode GaN photocathode was built, and based on the model the functional relations of thin film thickness and optical adsorption coefficient with transmission spectral were deduced. The error of calculated GaN epitaxial thickness with respect to actual value is very small, and calculated adsorption coefficients are consistent with reported data. It was shown that material structure and optical property of transmission-mode GaN photocathode can be evaluated accurately by this ultraviolet transmission spectral method.