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Abstract Gas sensors are useful for monitoring of greenhouse gases. As the move toward complementary metal‐oxide‐semiconductor (CMOS) compatible pyroelectric room temperature detectors is gaining traction due to its scalability to 8‐in./12‐in. wafer area and integrable with CMOS electronics, CMOS compatible aluminum nitride (AlN)‐ and scandium aluminum nitride (ScAlN)‐based pyroelectric detectors are developed for sensing of CO2and CH4gases, which are two of the greenhouse gases that contribute significantly to global warming. Leveraging gas absorption at respective mid‐infrared (IR) wavelengths, CO2 and CH4 gases are detected at various concentrations with fast response time ≈1 s. A compound parabolic collector (CPC) is designed and integrated into the gas sensor to enhance the optical flux received by the detector, which demonstrates ≈10× signal improvement in its presence. Further factors such as the effect of sensing area reduction and response to random gas concentrations are also tested on AlN‐ and ScAlN‐based pyroelectric detectors respectively to observe the gas sensing behaviors of both detectors. The results obtained provide further understanding of the behavior of CMOS AlN‐ and ScAlN‐based pyroelectric detectors as IR gas sensors, which can potentially inspire new design and design selection for various gas sensing applications.

Low temperature (200°C) direct bonding of InP and Si3N4 coated silicon wafers using oxygen plasma surface treatment has been demonstrated, which transfers InP-based thin films onto Si substrates for heterogeneous photonic integration. Pulling test shows a high bonding energy comparable to the InP fracture energy. The high crystalline quality of the bonded thin film is preserved, as evident from photoluminescence and high resolution X-ray diffraction measurements. Cross-sectional transmission electron microscopy shows an intimately bonded interface with no observable defects generated near the bonded interface. A thin layer of amorphous oxide about 6 nm thick has been detected at the bonded interface. The hydrophilic interface obtained by oxygen plasma activation helps to achieve high quality bonding. Due to the high thermal conductivity of Si3N4, these high quality bonded structures of InP/Si with Si3N4 sandwiched in-between have potential applications in enhancing performance of high power Si photonic integrated devices. [ABSTRACT FROM AUTHOR]