In this work, we theoretically demonstrate that the ultimate detectivities in multi-stage interband cascade infrared photodetector configurations are higher than what can be achieved in a conventional single-absorber detector structure in any circumstance even including where carrier diffusion length is very long. Detailed derivations are provided to analytically show that in the limit of an infinite diffusion length, the ultimate detectivity of a multiple-stage device is about 11% higher than that of an optimized single-stage device. Furthermore, how the sequence of absorber thicknesses is optimized for maximizing the detectivity is described and discussed. Insights and explanations to the results are presented to improve the understanding, clarify possible confusion with different perspectives in the technical community, and to generate more interest in the development of advanced multi-stage interband cascade infrared photodetectors for various applications.

中文翻译：

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多级带间级联红外光电探测器的终极探测能力

在这项工作中，我们从理论上证明了多级带间级联红外光电探测器配置的最终探测率高于传统单吸收器探测器结构在任何情况下都能达到的探测率，甚至包括载流子扩散长度很长的情况。提供了详细的推导以分析表明，在无限扩散长度的限制下，多级装置的最终检测率比优化的单级装置高约 11%。此外，描述和讨论了如何优化吸收器厚度的顺序以最大化检测率。提供对结果的见解和解释，以提高理解，澄清技术社区中不同观点的可能混淆，