Mid-infrared (MIR) silicon photonics holds the potential for realizing next generation ultra-compact spectroscopic systems for applications in gas sensing, defense and medical diagnostics. The direct epitaxial growth of antimonide-based compound semiconductors on silicon provides a promising approach for extending the wavelength of silicon photonics to the longer infrared range. This paper reports on the fabrication of a high performance MIR photodetector directly grown onto silicon by molecular beam epitaxy. The device exhibited an extended cut-off wavelength at ~5.5 μm and a dark current density of 1.4 x 10^-2 A/cm² under 100 mV reverse bias at 200 K. A responsivity of 0.88 A/W and a specific detectivity in the order of 1.5 x 10¹⁰ Jones was measured at 200 K under 100 mV reverse bias operation. These results were achieved through the development of an innovative structure which incorporates a type-II InAs/InAsSb superlattice-based barrier nBn photodetector grown on a GaSb-on-Silicon buffer layer. The difficulties in growing GaSb directly on silicon were overcome using a novel growth procedure consisting of an efficient AlSb interfacial misfit array, a two-step growth temperature procedure and dislocation filters resulting in a low defect density, anti-phase domain free GaSb epitaxial layer on silicon. This work demonstrates that complex superlattice-based MIR photodetectors can be directly integrated onto a Si platform, which provides a pathway towards the realization of new, high performance, large area focal plane arrays and mid-infrared integrated photonic circuits.

InAs thermophotovoltaic (TPV) cells with external quantum efficiency at the peak wavelengths reaching 71% at low temperature and 55% at room temperature are reported, which are the highest values to date for InAs. The TPV exhibited 10% power conversion efficiency at 100 K cell temperature. The dark and light current-voltage characteristics were measured at different cell temperatures (100–340 K) in response to heat sources in the range 500–800 °C. The resulting dependences of the output voltage and current as well as the spectral response of the InAs TPV have been extensively characterized for waste heat recovery applications. The performance of these cells is strongly determined by the dark current which increases rapidly with increasing cell temperature originating from bandgap narrowing, which resulted in a reduction of open circuit voltage and output power

In this work, 2-stage and 5-stage mid-infrared superlattice interband cascade light emitting diodes (ICLEDs) were fabricated and studied at different temperatures. The ICLEDs were composed of InAs/GaAsSb active regions, InAs/AlAsSb injection regions, and GaAsSb/AlAsSb tunneling regions. The devices exhibited high output power and very low series resistance, indicating efficient carrier blocking and tunneling in the designed structure. Radiances of 0.73 W/cm² sr and 0.38 W/cm² sr were achieved at 300 K for the 5-stage and 2-stage ICLEDs, respectively. With an output power of 3.56 mW, the wall-plug efficiency of the 5-stage ICLED reached 0.5% at 80 K, under an injection current of 350 mA. The efficiency was largely maintained in the same range with increasing current injection. The results showed that ICLEDs have great potential for mid-infrared light emitting diode applications requiring large output power and high wall-plug efficiency.

We report on a mid-infrared resonant cavity light emitting diode (RCLED) operating at the wavelength of 4.5 µm with a narrow spectral linewidth at room temperature. Compared to a reference LED without a resonant cavity, our RCLED exhibits (85x) higher peak intensity, (13x) higher integrated output power, (16x) narrower spectral linewidth and (7x) superior temperature stability. The device consists of a one-wavelength thick micro-cavity containing an Al_0.12In_0.88As/InAs_0.85Sb_0.15 quantum well active region sandwiched between two high contrast AlAs_0.08Sb_0.92/GaSb distributed Bragg reflector mirrors, grown lattice–matched on GaSb by molecular beam epitaxy. The high spectral brightness, narrow linewidth and superior temperature stability are attractive features, enabling these devices to be used for detection of N₂O at 4.5 µm. We show that with only minor adjustments the gases CO₂ (4.2 µm) and CO (4.6 µm) are also readily accessible.