Study on the Reflectivity of Distributed Bragg Reflector
- 航空航天－已发表论文 
从理论上推导出分布布拉格反射器(DBR)反射率的计算公式,分析了GaN基材料DBR反射率与单层膜折射率、多层膜的对数、单层膜的厚度等的关系,发现20对AlN/GaN构成的1/4波长DBR的反射率在中心波长410nm下达到了0.9995,分析了DBR反射率随单层厚度波动的影响,并发现随着正偏差的增大,最大反射率对应的波长增大.相同对数AlN/GaN多层膜的反射率比AlGaN/GaN多层膜的反射率大,因此,AlN/GaN比AlGaN/GaN更适合做反射器.The analytic expression of the reflectivity of d istributed Bragg reflector (DBR ) is deduced, and the relation between the reflectivity ofDBR and the refractive index of single layer, numbers of the peri- ods ofmulti-layer and the thickness of single layer is analyzed. When the incident light is 410 nanometer, the reflectivity of 20 periods of quarter-wave A lN /GaN DBR is attained to 0.999 5. Dependence of the reflectivity of a DBR on the thickness of single layer is d iscussed in detail. It is found that the wavelength atmaximum reflectivity increases with the positive warp of the thickness of single layer, and the reflectivity of a A lN /GaN DBR is larger than that of a A lGaN /GaN DBR with the same structural parameters. So, A lN /GaN is more compatible material for DBR than A lGaN /GaN.