针对带间级联结构在长波探测上的设计应用, 采用包络函数近似下的二带模型和传输矩阵方法, 考虑电子和轻空穴耦合, 计算了带间级联结构多量子阱弛豫区的E-k关系和详细能带信息.特别优化了弛豫区结构, 在保证光生载流子在弛豫区中隧穿几率的前提下首次利用周期性量子阱结构拓展弛豫区厚度, 降低吸收区中电场强度, 抑制产生复合电流和隧穿电流, 提高器件电学性能.制备的该两级结构长波带间级联探测器10.5μm处量子效率达到了20%, 证实了弛豫区与隧穿区具有良好的光生载流子输运.器件在80 K下50%截止波长为11.5μm, 是目前所见报道中带间级联结构在80 K工作温度下所获得最长波长的红外探测器.

Aiming at the design and application of the interband cascade structure in long wavelength detection, E-k relation and energy band information of multi-quantum-well relaxation region were calculated by using two-band model under the envelope-function approach and transfer matrix method. The structure of relaxation region was specially optimized. On the premise of the tunneling process of photon-generated carriers in relaxation region, the electric field of absorption region was reduced to suppress generation-recombination current and tunneling current, and to improve the electrical performance of device. The quantum efficiency of prepared double-stage interband cascade photodetector was up to 20% at 10.5 μm, which proved that the relaxation region and tunneling region had well transport of photoexcited carriers. The 50% cutoff wavelength of the device was 11.5 μm at 80 K, which was the longest wavelength infrared detector of interband cascade structure at 80 K.