We report the growth of InSb/CdTe hetero-epitaxial thin films on the GaAs (111)B substrate using molecular beam epitaxy. The use of (111) orientation enables the fast strain relaxation during the CdTe buffer layer growth, and major crystallographic defects are confined near the CdTe/GaAs interface. Owing to the lattice matching between InSb and CdTe, layer-by-layer 2D growth of InSb is observed from the initial growth stage. Both smooth surface morphology and low defect density of the as-grown InSb/CdTe heterostructures give rise to the enhancement of electron mobility when the InSb layer thickness is reduced below 30 nm as compared to the InSb/GaAs counterparts. The integration of InSb/CdTe highlights the advantage of lattice-matched epitaxial growth and provides a promising approach to design high-quality III–V/II–VI hybrid systems for high-performance device applications.
A germanium (Ge) or germanium-on-silicon (Ge-on-Si) substrate is an attractive yet not well-studied platform for developing long-wave infrared photonics devices such as lasers and photodetectors. In this paper, we report a long-wave infrared quantum cascade photodetector grown on the Ge substrate with a submonolayer InAs/GaAs quantum dot as the infrared absorber. At 77 K under zero bias, the detector shows a differential-resistance area (R0A) product of 298.7 Ω·cm2. The normal-incident peak responsivity is 0.56 mA/W observed at 8.3 μm, corresponding to a Johnson noise limited detectivity of 1.5 × 108 cm·Hz1/2/W. In addition, the effect of the periodic stage number of active regions on device's performance is discussed in detail. The device characteristics presented in this work demonstrate the potential for monolithic integration of this quantum cascade detector with the Ge or Ge-on-Si substrate for large-scale, cost-effective sensing and imaging applications.
Bound states in the continuum (BICs) can make subwavelength dielectric resonators sustain low radiation leakage, paving a new way to minimize the device size, enhance photoluminescence, and even realize lasing. Here, we present a quasi-BIC-supporting GaAs nanodisk with embedded InAs quantum dots as a compact bright on-chip light source, which is realized by heterogeneous integration, avoiding complex multilayered construction and subsequent mismatch and defects. The emitters are grown inside the nanodisk to match the mode field distribution to form strong light–matter interaction. One fabricated sample demonstrates a photoluminescence peak sustaining a quality factor up to 68 enhanced by the quasi-BIC, and the emitting effect can be further promoted by improving the epilayer quality and optimizing the layer-transferring process in the fabrication. This work provides a promising solution to building an ultracompact optical source to be integrated on a silicon photonic chip for high-density integration.
In this paper we reported the electrical and spectral properties of 1 MeV electron and 3 MeV proton irradiated In0.53Ga0.47As single junction solar cell, which is used as the fourth subcell of wafer bonded GaInP/GaAs//InGaAsP/InGaAs four-junction full spectra solar cell. The equivalent displacement damage dose model was applied to study the radiation effects of solar cell. The results show that the electrical parameters of the solar cell degrade seriously with the increase of irradiation fluences, the reduction of minority carrier life-time and changes of series and shunt resistance caused by irradiation-induced displacement damage are the main reason for the degradation of cell performance. Degradation of spectral response mainly occurred in the long wavelength region of solar cell due to the bigger displacement damage in the base layer of solar cell. Degradation properties of solar cell by electron and proton irradiation can be predicted by electron to proton damage equivalency factor Rep.
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