AlN/InN和AlN/GaN超晶格能带结构研究

Investigation on the band structures of AlN/InN and AlN/GaN superlattices

利用Krnig-Penney模型和形变势理论,从理论上探讨了纤锌矿型AlN/InN和AlN/GaN超晶格系统的能带结构及不同应变模式对能带结构的影响,计算得到了能带结构随各亚层参量变化的一般性规律、超晶格的能量色散关系、应变造成的影响以及不同亚层厚度的系统禁带宽度和导带第一子禁带宽度.研究发现,通过改变亚层厚度可以从不同形式设计能带结构,应变会改变系统禁带宽度,使带阶和子能带明显窄化,价带结构趋于复杂甚至生成准能带结构.与实验结果对比后发现,该模型适于模拟窄势阱结构超晶格,而对于宽势阱则必须考虑内建电场的作用.

The band structures of wurtzite-AlN/InN and AlN/GaN superlattices are calculated by the Krnig-Penney model and the deformation potential theory under considering the lattice strain.Our calculations include the variation of band structure with the parameters for the sublayers,and the energy dispersion relations.It is found that by varying the sublayer thickness,the band structures can be well designed in different ways.The strain will change the bandgaps,reduce the band offsets and the sub-bands obviously,and make the valence band more complex.In comparison with the experimental results,our model is rather suited for simulating the narrow-quantum-well structures,while for the wide-quantum-well structures,the build-in field should be considered.