Resonant cavity-enhanced photodiodes targeted within the spectral region of absorption by CH bonds are demonstrated. The $3.0$– $3.3\mu \text{m}$ region of the infrared spectrum contains many substances that are useful to measure spectroscopically. However, the measurement of individual substances requires a high spectral specificity, that is achieved by the resonant cavity photodiodes with spectral response widths of $<40\text{nm}$. Two material systems are investigated for detection at this wavelength range—an InAs absorber on an InAs substrate and an InAsSb absorber lattice-matched to a GaSb substrate. The resonance wavelength of the InAs-based device responds at $\approx 3.3\mu \text{m}$, closely tuned to an absorption peak of methane to allow precise sensing of this gas. At $300\mathrm{K}$ a quantum efficiency of $52\%$ is achieved, with a specific detectivity of $2.5\times {10}^{10}\text{cm}\sqrt{\text{Hz}}/W$. The InAsSb-based device is sensitive at $\approx 3.7\mu \mathrm{m}$, but the structure could be tuned to the methane absorption peak. Devices could be simply created to target other substances in the C−H absorption region by altering the layer thicknesses in the structure. Both structures can be used for spectrally specific gas sensing in this region of the infrared.

中文翻译：

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用于 C?H 键光谱的谐振腔增强型光电二极管

演示了以 C  H 键吸收的光谱区域内为目标的谐振腔增强型光电二极管。这$3.0$—— $3.3\mu \text{米}$红外光谱区域包含许多可用于光谱测量的物质。然而，单个物质的测量需要高光谱特异性，这是通过具有光谱响应宽度的谐振腔光电二极管实现的$<40\text{纳米}$. 研究了两种材料系统用于在该波长范围内进行检测——InAs 衬底上的 InAs 吸收剂和与 GaSb 衬底晶格匹配的 InAsSb 吸收剂。InAs 基器件的共振波长响应于$\approx 3.3\mu \text{米}$，密切调整到甲烷的吸收峰，以实现对这种气体的精确感应。在$300\mathrm{钾}$ 量子效率 $52\%$ 达到了，具有特定的检测能力 $2.5\times {10}^{10}\text{厘米}\sqrt{\text{赫兹}}/宽$. 基于 InAsSb 的器件在$\approx 3.7\mu \mathrm{米}$，但结构可以调整到甲烷吸收峰。通过改变结构中的层厚度，可以简单地创建器件以针对 CH 吸收区域中的其他物质。两种结构都可用于该红外区域的光谱特定气体传感。