Night vision applications utilize the reflected nightglow radiation in the short-wavelength infrared (SWIR) atmospheric window. Nevertheless, the low light intensity values require dark current densities on the order of ${\rm nA}/{{\rm cm}^2}$ for detection around room temperature. Currently, with new device architectures and developments in growth and surface passivation, very low dark current density values are achievable for 1.7 µm cutoff InGaAs detectors near room temperature, and such detectors seem to be the leading choice for the nightglow detection applications. On the other hand, HgCdTe has not been thoroughly investigated for low-cost nightglow detection with 1.7 µm cutoff, primarily due to its manufacture expenses for lattice-matched CdZnTe growth. In this study, we analyze the nightglow radiation detecting performance of the alternative substrate HgCdTe detectors near room temperature (${\rm T} = {270}\;{\rm K}$) using computer simulations. It is assessed that alternative substrate HgCdTe cannot attain the required dark current density values due to Shockley–Read–Hall (SRH) recombination in the depletion region, if the heterojunction photodiode structure is adopted. To overcome the problem, depletion-engineered devices are designed where the depletion region is embedded within a larger bandgap HgCdTe, which suppresses the depletion region SRH $\sim{1300}$ times. This reduces the dark current density to the desired order, for SRH lifetimes achievable with alternative substrate growth. Dark current densities as low as ${0.26}\;{{\rm nA/cm}^2}$ are shown to be possible for an SRH lifetime of $\tau = {3}\;{\unicode{x00B5}{\rm s}}$ while maintaining the quantum efficiency $\sim{85}\% $. With this approach benefiting from alternative substrates and depletion engineering, HgCdTe can achieve InGaAs nightglow imaging performances near room temperature, and can benefit from less costly manufacture and broader application capability for nightglow radiation detection.

中文翻译：

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在替代基板上使用耗竭工程化的HgCdTe在室温下进行SWIR夜光辐射检测

夜视应用程序利用短波红外（SWIR）大气窗口中反射的夜光辐射。但是，低光强度值需要大约$ {\ rm nA} / {{\ rm cm} ^ 2} $的暗电流密度用于室温附近的检测。当前，随着新器件架构的发展以及生长和表面钝化的发展，对于接近室温的1.7 µm截止InGaAs检测器，可以实现非常低的暗电流密度值，并且这种检测器似乎是夜光检测应用的首选。另一方面，尚未对HgCdTe进行低成本的夜光检测（截止值为1.7 µm）进行彻底的研究，这主要是由于HgCdTe用于晶格匹配的CdZnTe生长的制造费用。在这项研究中，我们分析了室温附近（$ {\ rm T} = {270} \; {\ rm K} $）使用计算机模拟。据评估，如果采用异质结光电二极管结构，由于耗尽区中的Shockley-Read-Hall（SRH）重组，替代衬底HgCdTe无法达到所需的暗电流密度值。为了克服该问题，设计了耗尽工程设计的器件，其中耗尽区嵌入在较大的带隙HgCdTe中，从而抑制了耗尽区SRH \ sim {1300} $倍。对于通过替代衬底生长可获得的SRH寿命，这将暗电流密度降低到所需的数量级。暗电流密度低至$ {0.26} \; {{\ rm nA / cm} ^ 2} $在SRH寿命$ \ tau = {3} \; {\ unicode {x00B5} { \ rm s}} $同时保持量子效率$ \ sim {85} \％$。通过受益于替代衬底和耗尽工程技术的这种方法，HgCdTe可以在接近室温的情况下实现InGaAs夜光成像性能，并且可以受益于成本更低的制造和更广泛的夜光辐射检测应用能力。