Midwave Infrared Quantum Dot Quantum Cascade Photodetector Monolithically Grown on Silicon Substrate

Abstract

Mid-infrared photodetector based on sub-monolayer (SML) quantum dot quantum cascade structure monolithically grown on silicon substrate has been demonstrated in this work. Both the optical and electrical characteristics of the SML quantum dot quantum cascade photodetectors (QD-QCD) were analyzed quantitatively. The performances of these devices were compared with that on native GaAs substrate. A large resistance-area (R0A) product of 1.13×10 7 Ω.cm 2 is achieved at 77 K for the silicon based devices, which is only roughly one order less than that on GaAs substrate. The device shows a normal-incident peak responsivity of 0.59 mA/W under zero bias at the wavelength of 6.2 μm at 77 K, indicating a photovoltaic operation mode. Johnson noise limited specific detectivity is 3×10 10 cm•Hz 1/2 /W at 77 K, with photoresponse up to 100 K. These results suggest that the silicon-based QD-QCD in this work is a very promising candidate for large format mid-infrared focal plane array and mid-infrared silicon photonics applications.

Biosynthesis and Antibacterial Activity of Silver Nanoparticles Using Yeast Extract as Reducing and Capping Agents

“…The size, shape, and surface chemistry of Ag NPs showed an important effect on the antimicrobial activity. The smaller size and higher surface area allowed the Ag NPs to Scheme 1 Proposed schematic illustration of the biosynthesis of Ag NPs better interact with the bacterial membrane for further enhanced antimicrobial activity [15][16][17]. The clear lattice fringes in the HRTEM image showed a fringe spacing of 0.15 nm ( Fig.…”

Defect Characterization of InAs/InGaAs Quantum Dot p-i-n Photodetector Grown on GaAs-on-V-Grooved-Si Substrate

“…where τr is the recombination lifetime, kB is the Boltzmann constant, T is the device temperature, ET and Ei are the energy level of defect and intrinsic Fermi level, respectively. A recombination lifetime of 27 μs is obtained by eq (6). Finally, a trap density of Nt=5.4×10 12 cm -3 was estimated using the following formula:…”

“…Furthermore, the III-V QDs on Si structure demonstrated in this work could also operate as a laser diode on Si as they share the same epitaxial structure 14 , the defect information and the lifetime obtained in this work correlates to the amplitude of non-radiative recombination process, which is critical for laser threshold analysis and laser dynamics modeling to investigate the thermal characteristics, relaxation oscillation parameter and modulation properties [30][31] . It is also noted that using a n-i-n structure, a slight variation of the current p-i-n structure, the current near-infrared photodetector structure can be transferred into quantum dot infrared photodetector (QDIP) structure utilizing inter-subband absorption to detect mid-wavelength infrared light, which has important applications in both civil and military areas [5][6]32 . The density of deep traps and trap energy levels play an important role with the QD energy levels to model the self-consistent band bending and space charge distribution, which determines the electron occupancy in QDs, a critical parameter in inter-subband QDIP device to further optimize the dark current and responsivity performance 27 .…”

Ag2S QDs/Si Heterostructure-Based Ultrasensitive SWIR Range Detector

“…Another approach is based on the integration of non-silicon electro-optical materials, such GaAs, InAs. This approach is strongly limited by the mismatch between the lattice of Si and the lattice of these materials; however, significant progress has recently been made in the fabrication and study of high-quality structures based on materials from groups III-V grown on an Si substrate [20][21][22][23]. Commercially available Si:As impurity band conduction detectors are widely used for the detection of IR radiation with wavelengths of 5-28 um [24,25].…”